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2024-2025 ICPC Asia Jakarta Regional Contest (Unrated, Online Mirror, ICPC Rules, Teams Preferred)/C. Saraga.cpp

@@ -0,0 +1,146 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2045/C */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 0
+
+void solve()
+{
+    string s, t;
+    cin >> s >> t;
+
+    int in = -1;
+    int jn = -1;
+    int ans = oo;
+
+    vi pos(26, -1);
+    rep(i, t.size() - 1) {
+        pos[t[i] - 'a'] = i;
+    }
+
+    nrep(i, 1, s.size()) {
+        int cur = s[i] - 'a';
+
+        if (pos[cur] == -1) {
+            continue;
+        }
+
+        int c = i + t.size() - pos[cur] + 1;
+        if (c < ans) {
+            ans = c;
+            in = i;
+            jn = pos[cur];
+        }
+    }
+
+    if (ans == oo) {
+        cout << "-1\n";
+        return;
+    }
+
+    rep(i, in) {
+        cout << s[i];
+    }
+    
+    nrep(j, jn, t.size()) {
+        cout << t[j];
+    }
+
+    cout << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

2024-2025 ICPC Asia Jakarta Regional Contest (Unrated, Online Mirror, ICPC Rules, Teams Preferred)/M. Mirror Maze.cpp

@@ -0,0 +1,248 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2045/M */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 0
+
+void solve()
+{
+    int r, c;
+    cin >> r >> c;
+
+    V<string> a(r);
+    cin >> a;
+
+    auto getpos = [&](int i, int j, int k) {
+        return i * c * 4 + j * 4 + k;
+    };
+
+    int tot = 0;
+
+    vvi graph(r * c * 4);
+    vi ty(r * c * 4, -1);
+    rep(i, r) {
+        rep(j, c) {
+            int n = getpos(i, j, 0);
+            int e = getpos(i, j, 1);
+            int s = getpos(i, j, 2);
+            int w = getpos(i, j, 3);
+
+            if (i > 0) {
+                int ot = getpos(i - 1, j, 2);
+                graph[n].push_back(ot);
+            }
+
+            if (j > 0) {
+                int ot = getpos(i, j - 1, 1);
+                graph[w].push_back(ot);
+            }
+
+            if (i < r - 1) {
+                int ot = getpos(i + 1, j, 0);
+                graph[s].push_back(ot);
+            }
+
+            if (j < c - 1) {
+                int ot = getpos(i, j + 1, 3);
+                graph[e].push_back(ot);
+            }
+
+            if (a[i][j] == '.') {
+                graph[e].push_back(w);
+                graph[w].push_back(e);
+                graph[s].push_back(n);
+                graph[n].push_back(s);
+                continue;
+            }
+            tot++;
+            ty[n] = i * c + j;
+            ty[e] = i * c + j;
+            ty[s] = i * c + j;
+            ty[w] = i * c + j;
+
+            if (a[i][j] == '/') {
+                graph[n].push_back(w);
+                graph[w].push_back(n);
+                graph[s].push_back(e);
+                graph[e].push_back(s);
+                continue;
+            }
+
+            graph[n].push_back(e);
+            graph[e].push_back(n);
+            graph[w].push_back(s);
+            graph[s].push_back(w);
+        }
+    }
+
+    V<bool> vis(r * c * 4);
+    vi sz(r * c * 4, -1);
+
+    set<int> s;
+    function<void(int)> dfs = [&](int i) {
+        vis[i] = true;
+        if (ty[i] != -1) {
+            s.insert(ty[i]);
+        }
+
+        repv(j, graph[i]) {
+            if (vis[j]) {
+                continue;
+            }
+
+            dfs(j);
+        }
+    };
+
+    function<void(int)> dfs2 = [&](int i) {
+        sz[i] = s.size();
+
+        repv(j, graph[i]) {
+            if (sz[j] != -1) {
+                continue;
+            }
+
+            dfs2(j);
+        }
+    };
+
+    rep(i, r) {
+        rep(j, c) {
+            rep(k, 4) {
+                int ac = getpos(i, j, k);
+                if (vis[ac]) {
+                    continue;
+                }
+
+                dfs(ac);
+                dfs2(ac);
+                s.clear();
+            }
+        }
+    }
+
+    V<string> ans;
+    rep(i, r) {
+        int w = getpos(i, 0, 3);
+        if (sz[w] == tot) {
+            ans.emplace_back("W" + to_string(i + 1));
+        }
+        int e = getpos(i, c - 1, 1);
+        if (sz[e] == tot) {
+            ans.emplace_back("E" + to_string(i + 1));
+        }
+    }
+
+    rep(i, c) {
+        int n = getpos(0, i, 0);
+        if (sz[n] == tot) {
+            ans.emplace_back("N" + to_string(i + 1));
+        }
+        int s = getpos(r - 1, i, 2);
+        if (sz[s] == tot) {
+            ans.emplace_back("S" + to_string(i + 1));
+        }
+    }
+
+    cout << ans.size() << '\n';
+    repv(i, ans) {
+        cout << i << ' ';
+    }
+    cout << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

2025-2026 ICPC, NERC, Northern Eurasia Finals (Unrated, Online Mirror, ICPC Rules, Teams Preferred)/F. Fragmented Nim.cpp

@@ -0,0 +1,118 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2181/F */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+    vl a(n);
+    cin >> a;
+
+    int c = 0;
+    bool t = false;
+    rep(i, n) {
+        c += a[i] == 1;
+        t = t || a[i] != 1;
+    }
+
+    cout << (((c & 1) && !t) || ((~c & 1) && t) ? "Alice\n" : "Bob\n");
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 1064 (Div. 1)/B. Marble Council.cpp

@@ -0,0 +1,138 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2165/B */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+
+    ll mod = 998244353;
+
+    vl c(n);
+    ll ma = 0;
+    rep(i, n) {
+        int a;
+        cin >> a;
+        c[a - 1]++;
+        rmax(ma, c[a - 1]);
+    }
+
+    vl dp(n + 1);
+    dp[0] = 1;
+
+    rep(i,  n) {
+        if (c[i] == 0) {
+            continue;
+        }
+
+        for (int j = n; j >= c[i]; j--) {
+            (dp[j] += dp[j - c[i]] * c[i]) %= mod;
+        }
+    }
+
+    ll ans = 0;
+    nrep(i, ma, n + 1) {
+        (ans += dp[i]) %= mod;
+    }
+
+    cout << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 1074 (Div. 4)/F. BattleCows.cpp

@@ -0,0 +1,155 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2185/F */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n, q;
+    cin >> n >> q;
+    int sz = 1 << n;
+
+    vl a(sz);
+    cin >> a;
+
+    vl an(sz * 2);
+
+    function<ll(int)> calc = [&](int i) {
+        if (i >= sz) {
+            an[i] = a[i - sz];
+            return an[i];
+        }
+
+        ll a1 = calc(i * 2);
+        ll a2 = calc(i * 2 + 1);
+
+        an[i] = a1 ^ a2;
+        return an[i];
+    };
+
+    calc(1);
+
+    while (q--) {
+        int b, c;
+        cin >> b >> c;
+
+        ll ans = 0;
+        ll cur = a[b - 1];
+        bool add = false;
+        int st = 0;
+        b += sz;
+        b--;
+
+        while (b > 1) {
+            int now = b & 1;
+            b >>= 1;
+
+            ll cur = an[(b << 1) + (now ^ 1)];
+            if (cur > c || (cur == c && now)) {
+                ans += 1 << st;
+            }
+
+            st++;
+            c ^= cur;
+        }
+        
+        cout << ans << '\n';
+    }
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 957 (Div. 3)/F. Valuable Cards.cpp

@@ -0,0 +1,137 @@
+/* Problem URL: https://codeforces.com/problemset/problem/1992/F */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n, x;
+    cin >> n >> x;
+
+    vi a(n);
+    cin >> a;
+
+    set<int> ev;
+    ev.insert(x);
+
+    int ans = 1;
+    rep(i, n) {
+        set<int> tmp = ev;
+        repv(j, ev) {
+            if (j % a[i] == 0) {
+                tmp.insert(j / a[i]);
+            }
+        }
+
+        if (tmp.count(1)) {
+            ans++;
+            ev.clear();
+            ev.insert(x);
+            if (x % a[i] == 0) {
+                ev.insert(x / a[i]);
+            }
+            continue;
+        }
+
+        swap(ev, tmp);
+    }
+
+    cout << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 966 (Div. 3)/E. Photoshoot for Gorillas.cpp

@@ -0,0 +1,167 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2000/E */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n, m, k;
+    cin >> n >> m >> k;
+
+    int w;
+    cin >> w;
+    vl a(w);
+    cin >> a;
+
+    vvl c(n, vl(m));
+    rep(i, n - k + 1) {
+        rep(j, m - k + 1) {
+            c[i][j]++;
+            int id = i + k;
+            int jd = j + k;
+
+            if (id < n) {
+                c[id][j]--;
+            }
+
+            if (jd < m) {
+                c[i][jd]--;
+            }
+
+            if (id < n && jd < m) {
+                c[id][jd]++;
+            }
+        }
+    }
+
+    rep(i, n) {
+        rep(j, m) {
+            if (i > 0) {
+                c[i][j] += c[i - 1][j];
+            }
+
+            if (j > 0) {
+                c[i][j] += c[i][j - 1];
+            }
+
+            if (i > 0 && j > 0) {
+                c[i][j] -= c[i - 1][j - 1];
+            }
+        }
+    }
+
+    vi t;
+    rep(i, n) {
+        rep(j, m) {
+            t.push_back(c[i][j]);
+        }
+    }
+
+    sort(all(t), greater<>());
+    sort(all(a), greater<>());
+
+    ll ans = 0;
+
+    rep(i, w) {
+        ans += a[i] * t[i];
+    }
+
+    cout << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 972 (Div. 2)/C. Lazy Narek.cpp

@@ -0,0 +1,156 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2005/C */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+bool inv[256];
+
+void pre()
+{
+    inv['n'] = true;
+    inv['a'] = true;
+    inv['r'] = true;
+    inv['e'] = true;
+    inv['k'] = true;
+}
+
+#define TEST 1
+
+string fd = "narek";
+
+void solve()
+{
+    int n, m;
+    cin >> n >> m;
+
+    V<string> a(n);
+    cin >> a;
+
+
+    vvl memo(n, vl(5, -OO));
+
+    function<ll(int, int)> dp = [&](int i, int f) {
+        if (i >= n) {
+            return (ll)-f;
+        }
+
+        ll &ans = memo[i][f];
+        if (ans != -OO) {
+            return ans;
+        }
+
+        int pr = f;
+
+        ans = 0;
+        repv(j, a[i]) {
+            if (j == fd[f]) {
+                ans += 5 * (f == 4);
+                f = f + 1 - 5 * (f == 4);
+                continue;
+            }
+
+            ans -= inv[j];
+        }
+
+        ll tmp = -OO;
+        rmax(tmp, dp(i + 1, f));
+
+        return ans = max({ans + tmp, ans - f, dp(i + 1, pr)});
+    };
+
+    ll ans = 0;
+    rep(i, n) {
+        rmax(ans, dp(i, 0));
+    }
+
+    cout << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 976 (Div. 2) and Divide By Zero 9.0/C. Bitwise Balancing.cpp

@@ -0,0 +1,139 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2020/C */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    ll b, c, d;
+    cin >> b >> c >> d;
+
+    ll ans = 0;
+    rep(i, 61) {
+        int bi = (b >> i) & 1;
+        int ci = (c >> i) & 1;
+        ll di = (d >> i) & 1;
+
+        if (bi && ci) {
+            ans |= (di^1) << i;
+            continue;
+        }
+
+        if (bi && !ci) {
+            if (!di) {
+                cout << "-1\n";
+                return;
+            }
+            continue;
+        }
+
+        if (!bi && ci) {
+            if (di) {
+                cout << "-1\n";
+                return;
+            }
+            continue;
+        }
+
+        ans |= di << i;
+    }
+    
+    cout << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 984 (Div. 3)/E. Reverse the Rivers.cpp

@@ -0,0 +1,180 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2036/E */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 0
+
+void solve()
+{
+    int n, m, q;
+    cin >> n >> m >> q;
+
+    vvl a(n, vl(m));
+    cin >> a;
+
+    rep(j, m) {
+        nrep(i, 1, n) {
+            a[i][j] |= a[i - 1][j];
+        }
+    }
+
+    while (q--) {
+        int l = 0;
+        int r = n - 1;
+
+        int q;
+        cin >> q;
+        while (q--) {
+            int p;
+            char op;
+            ll c;
+            cin >> p >> op >> c;
+            p--;
+
+            auto findl = [&]() {
+                int low = l;
+                int high = n - 1;
+                int ans = n;
+                while (low <= high) {
+                    int mid = (low + high) >> 1;
+
+                    if (a[mid][p] > c) {
+                        ans = mid;
+                        high = mid - 1;
+                        continue;
+                    }
+
+                    low = mid + 1;
+                }
+                return ans;
+            };
+
+            auto findr = [&]() {
+                int low = 0;
+                int high = r;
+                int ans = -1;
+                while (low <= high) {
+                    int mid = (low + high) >> 1;
+
+                    if (a[mid][p] < c) {
+                        ans = mid;
+                        low = mid + 1;
+                        continue;
+                    }
+
+                    high = mid - 1;
+                }
+                return ans;
+            };
+
+            if (op == '>') {
+                l = findl();
+            } else {
+                r = findr();
+            }
+        }
+
+        if (l > r) {
+            cout << "-1\n";
+            continue;
+        }
+
+        cout << l + 1 << '\n';
+    }
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Educational Codeforces Round 144 (Rated for Div. 2)/D. Maximum Subarray.cpp

@@ -0,0 +1,147 @@
+/* Problem URL: https://codeforces.com/problemset/problem/1796/D */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+constexpr int MAXN = 2e5 + 10;
+constexpr int MAXK = 30;
+ll memo[MAXN][MAXK][4];
+
+void solve()
+{
+    int n, k;
+    ll x;
+    cin >> n >> k >> x;
+
+    vl a(n);
+    cin >> a;
+
+    ll otinf = -OO / 4;
+    vvvl memo(n, vvl(k + 1, vl(3, -OO)));
+
+    function<ll(int, int, int)> dp = [&](int i, int j, int s) {
+        if (j > k) {
+            return otinf;
+        }
+
+        if (i >= n) {
+            return j == k ? 0LL : otinf;
+        }
+
+        ll &ans = memo[i][j][s];
+        if (ans != -OO) {
+            return ans;
+        }
+
+        if (s == 0) {
+            return ans = max({dp(i + 1, j, 0), dp(i + 1, j + 1, 0),
+                             dp(i + 1, j + 1, 1) + a[i] + x, dp(i + 1, j, 1) + a[i] - x});
+        }
+
+        if (s == 1) {
+            return ans = max({dp(i + 1, j, 1) + a[i] - x, dp(i + 1, j + 1, 1) + a[i] + x,
+                             dp(i + 1, j, 2), dp(i + 1, j + 1, 2)});
+        }
+
+        return ans = max(dp(i + 1, j + 1, 2), dp(i + 1, j, 2));
+    };
+
+    cout << dp(0, 0, 0) << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Hello 2023/C. Least Prefix Sum.cpp

@@ -0,0 +1,160 @@
+/* Problem URL: https://codeforces.com/problemset/problem/1779/C */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n, m;
+    cin >> n >> m;
+
+    vl a(n);
+    cin >> a;
+
+    m--;
+
+    int ans = 0;
+    vl pref(n + 1);
+
+    nrep(i, 1, n + 1) {
+        pref[i] = pref[i - 1] + a[i - 1];
+    }
+    pref[0] = OO;
+
+    priority_queue<pair<ll, int>> pq;
+
+    ll cur = pref[m + 1];
+    for (int i = m; i >= 0; i--) {
+        pq.emplace(a[i], i);
+
+        while (cur > pref[i]) {
+            auto [c, j] = pq.top();
+            pq.pop();
+            a[j] = -a[j];
+            cur -= c * 2;
+            ans++;
+        }
+    }
+
+    while (!pq.empty()) {
+        pq.pop();
+    }
+
+    pref[0] = 0;
+    nrep(i, 1, n + 1) {
+        pref[i] = pref[i - 1] + a[i - 1];
+    }
+
+    priority_queue<ll, vl, greater<>> mpq;
+
+    cur = pref[m + 1];
+    nrep(i, m + 1, n) {
+        cur += a[i];
+        mpq.push(a[i]);
+
+        while (cur < pref[m + 1]) {
+            cur -= mpq.top() * 2;
+            mpq.pop();
+            ans++;
+        }
+    }
+
+    cout << ans << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

problemlist.md

@@ -97,7 +97,18 @@ A little collection of interesting problems that I randomly decided to do.
 	
 - [D. Jellyfish and Mex](https://codeforces.com/problemset/problem/1875/D)
 
-	An interesting problem to thinkm about.
+	An interesting problem to think about.
+
+- [C. Lazy Narek](https://codeforces.com/problemset/problem/2005/C)
+
+	I just liked the problem, not particularly hard.
+
+- [D. Maximum Subarray](https://codeforces.com/problemset/problem/1796/D)
+
+	Interesting to think about the transitions and the states, although figuring out
+	it's a dp problem is already a challenge by itself.
+
+
 
 ## Graph
 
@@ -124,3 +135,10 @@ A little collection of interesting problems that I randomly decided to do.
 - [F. Non-academic Problem](https://codeforces.com/problemset/problem/1986/F)
 
 	Bridge to compress the graph into a tree.
+
+## Divide and Conquer
+
+- [F. BattleCows](https://codeforces.com/problemset/problem/2185/F)
+	
+	Interesting problem to think about, good introduction to divide and conquer in my opinion and
+	can be used as a bridge to segment trees.