Add more problems

Codeforces Round 889 (Div. 1)/A1. Dual (Easy Version).cpp

@@ -0,0 +1,177 @@
+/* Problem URL: https://codeforces.com/problemset/problem/1854/A1 */
+
+#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 mi = oo;
+    int mii = -1;
+    int ma = -oo;
+    int mai = -1;
+    rep(i, n) {
+        if (a[i] < mi) {
+            mi = a[i];
+            mii = i;
+        }
+
+        if (a[i] >= ma) {
+            ma = a[i];
+            mai = i;
+        }
+    }
+
+    if (ma == mi) {
+        cout << "0\n";
+        return;
+    }
+
+    V<pair<int, int>> ans;
+
+    auto printans = [&]() {
+        cout << ans.size() << '\n';
+        repv(i, ans) {
+            cout << i.first << ' ' << i.second << '\n';
+        }
+    };
+
+    if (ma > 0) {
+        ans.emplace_back(mai + 1, mai + 1);
+        ans.emplace_back(mai + 1, mai + 1);
+        ans.emplace_back(mai + 1, mai + 1);
+        ans.emplace_back(mai + 1, mai + 1);
+        ans.emplace_back(mai + 1, mai + 1);
+        ans.emplace_back(n, mai + 1);
+        ans.emplace_back(n, n);
+        ans.emplace_back(n, n);
+        ans.emplace_back(n, n);
+
+        rep(i, n) {
+            ans.emplace_back(i + 1, n);
+            ans.emplace_back(n, n);
+        }
+
+        printans();
+        return;
+    }
+
+    ans.emplace_back(mii + 1, mii + 1);
+    ans.emplace_back(mii + 1, mii + 1);
+    ans.emplace_back(mii + 1, mii + 1);
+    ans.emplace_back(mii + 1, mii + 1);
+    ans.emplace_back(mii + 1, mii + 1);
+    ans.emplace_back(mii + 1, mii + 1);
+    ans.emplace_back(1, mii + 1);
+    ans.emplace_back(1, 1);
+    ans.emplace_back(1, 1);
+    ans.emplace_back(1, 1);
+
+    for (int i = n - 1; i >= 0; i--) {
+        ans.emplace_back(i + 1, 1);
+        ans.emplace_back(1, 1);
+    }
+
+    printans();
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Codeforces Round 902 (Div. 1, based on COMPFEST 15 - Final Round)/B. Effects of Anti Pimples.cpp

@@ -0,0 +1,144 @@
+/* Problem URL: https://codeforces.com/problemset/problem/1876/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 0
+
+void solve()
+{
+    int n;
+    cin >> n;
+
+    vi a(n);
+    cin >> a;
+
+    vl c(2e5);
+
+    rep(i, n) {
+        for (int j = i + 1; j <= n; j += i + 1) {
+            rmax(a[i], a[j - 1]);
+        }
+        c[a[i]]++;
+    }
+
+    const ll mod = 998244353;
+
+    auto fpow = [&](ll a, ll p) {
+        ll ans = 1;
+        rep(i, 61) {
+            if ((p >> i) & 1) {
+                (ans *= a) %= mod;
+            }
+            (a *= a) %= mod;
+        }
+        return ans;
+    };
+
+    ll ans = 0;
+    for (int i = 2e5 - 1; i >= 0; i--) {
+        if (c[i] == 0) {
+            continue;
+        }
+
+        n -= c[i];
+        (ans += ((fpow(2, c[i]) - 1) % mod + mod) % mod * fpow(2, n) % mod * i % mod) %= 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 993 (Div. 4)/G2. Medium Demon Problem (hard version).cpp

@@ -0,0 +1,181 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2044/G2 */
+
+#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;
+    vi p(n);
+    vvi rev(n);
+    rep(i, n) {
+        cin >> p[i];
+        p[i]--;
+        rev[p[i]].push_back(i);
+    }
+
+    V<bool> vis(n);
+    V<bool> loop(n);
+    vvi ne(20, vi(n, -1));
+
+    rep(i, n) {
+        ne[0][i] = p[i];
+    }
+
+    function<void(int)> getloop = [&](int i) {
+        vis[i] = true;
+        int t = p[i];
+        int h = p[t];
+
+        while (t != h) {
+            if (vis[t]) {
+                return;
+            }
+
+            vis[t] = true;
+
+            t = p[t];
+            h = p[p[h]];
+        }
+
+        vis[t] = true;
+        loop[t] = true;
+        h = p[h];
+        while (h != t) {
+            loop[h] = true;
+            vis[h] = true;
+            h = p[h];
+        }
+    };
+
+    rep(i, n) {
+        if (vis[i]) {
+            continue;
+        }
+
+        getloop(i);
+    }
+
+    ll ans = 0;
+    function<ll(int)> dfs = [&](int i) {
+        ll ans = 1;
+        repv(j, rev[i]) {
+            ans += dfs(j);
+        }
+        return ans;
+    };
+
+    rep(i, n) {
+        if (!loop[i]) {
+            continue;
+        }
+
+        repv(j, rev[i]) {
+            if (loop[j]) {
+                continue;
+            }
+
+            rmax(ans, dfs(j));
+        }
+    }
+
+    cout << ans + 2 << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

Neowise Labs Contest 1 (Codeforces Round 1018, Div. 1 + Div. 2)/C. Wonderful City.cpp

@@ -0,0 +1,247 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2096/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;
+    cin >> n;
+
+    vvl h(n, vl(n));
+    cin >> h;
+
+    V<V<pair<int, ll>>> graph(n * 2);
+
+    auto addedge = [&](int u, int v, ll c)
+    {
+        graph[u].emplace_back(v, c);
+    };
+
+    vl a(n);
+    vl b(n);
+    cin >> a >> b;
+
+    vl memo(n * 2, -1);
+
+    function<ll(int)> dfs = [&](int i) {
+        if (i >= (n - 1) * 2) {
+            return 0LL;
+        }
+
+        ll &ans = memo[i];
+        if (ans != -1) {
+            return ans;
+        }
+
+        ans = OO;
+
+        repv(j, graph[i]) {
+            ll tmp = dfs(j.first);
+            if (tmp == OO) {
+                continue;
+            }
+
+            rmin(ans, tmp + j.second);
+        }
+
+        return ans;
+    };
+
+    rep(j, n - 1) {
+        int pos = (1 << 4) - 1;
+        int msk = (1 << 5) - 1;
+        rep(i, n) {
+            if (h[i][j] == h[i][j + 1]) {
+                pos &= msk ^ 1;
+                pos &= msk ^ (1 << 3);
+                continue;
+            }
+            
+            if (h[i][j] == h[i][j + 1] - 1) {
+                pos &= msk ^ (1 << 2);
+                continue;
+            }
+
+            if (h[i][j] - 1 == h[i][j + 1]) {
+                pos &= msk ^ (1 << 1);
+            }
+        }
+
+        if (pos == 0) {
+            cout << "-1\n";
+            return;
+        }
+
+        if (pos & 1) {
+            addedge(j * 2, (j + 1) * 2, 0);
+        }
+
+        if (pos & 2) {
+            addedge(j * 2, (j + 1) * 2 + 1, b[j + 1]);
+        }
+
+        if (pos & 4) {
+            addedge(j * 2 + 1, (j + 1) * 2, 0);
+        }
+
+        if (pos & 8) {
+            addedge(j * 2 + 1, (j + 1) * 2 + 1, b[j + 1]);
+        }
+    }
+    
+    ll ans = min(dfs(0), dfs(1) + b[0]);
+    if (ans >= OO) {
+        cout << "-1\n";
+        return;
+    }
+    graph.assign(n * 2, V<pair<int, ll>>());
+    fill(all(memo), -1);
+
+    rep(i, n - 1) {
+        int pos = (1 << 4) - 1;
+        int msk = (1 << 5) - 1;
+        rep(j, n) {
+            if (h[i][j] == h[i + 1][j]) {
+                pos &= msk ^ 1;
+                pos &= msk ^ (1 << 3);
+                continue;
+            }
+            
+            if (h[i][j] == h[i + 1][j] - 1) {
+                pos &= msk ^ (1 << 2);
+                continue;
+            }
+
+            if (h[i][j] - 1 == h[i + 1][j]) {
+                pos &= msk ^ (1 << 1);
+            }
+        }
+
+        if (pos == 0) {
+            cout << "-1\n";
+            return;
+        }
+
+        if (pos & 1) {
+            addedge(i * 2, (i + 1) * 2, 0);
+        }
+
+        if (pos & 2) {
+            addedge(i * 2, (i + 1) * 2 + 1, a[i + 1]);
+        }
+
+        if (pos & 4) {
+            addedge(i * 2 + 1, (i + 1) * 2, 0);
+        }
+
+        if (pos & 8) {
+            addedge(i * 2 + 1, (i + 1) * 2 + 1, a[i + 1]);
+        }
+    }
+
+    ll tmp = min(dfs(0), dfs(1) + a[0]);
+    if (tmp >= OO) {
+        cout << "-1\n";
+        return;
+    }
+
+    cout << ans + tmp << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}

problemlist.md

@@ -116,6 +116,15 @@ A little collection of interesting problems that I randomly decided to do.
 
 	Cool graph problem, not exactly difficult, but interesting to think about it.
 
+- [C. Wonderful City](https://codeforces.com/problemset/problem/2096/C)
+
+	Amazing graph/dp problem, actually interesting to think about it.
+
+- [G2. Medium Demon Problem (hard version)](https://codeforces.com/problemset/problem/2044/G2)
+
+	A very simple problem once you finally understand it, interesting to learn about dfs
+	and all that.
+
 ## Math
 
 - [E2. Rudolf and Snowflakes (hard version)](https://codeforces.com/problemset/problem/1846/E2)