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Educational Codeforces Round 34 (Rated for Div. 2)/A. Hungry Student Problem.cpp

@@ -0,0 +1,106 @@
+/* Problem URL: https://codeforces.com/contest/903/problem/A */
+
+#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;
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int t;
+    cin >> t;
+    while (t--) {
+        int n;
+        cin >> n;
+
+        bool valid = false;
+
+        rep(i, 101) {
+            rep(j, 101) {
+                if (3 * i + 7 * j == n) {
+                    valid = true;
+                    break;
+                }
+            }
+
+            if (valid) {
+                break;
+            }
+        }
+
+        cout << (valid ? "YES\n" : "NO\n");
+    }
+}

Educational Codeforces Round 34 (Rated for Div. 2)/B. The Modcrab.cpp

@@ -0,0 +1,114 @@
+/* Problem URL: https://codeforces.com/contest/903/problem/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;
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int h, a, c;
+    cin >> h >> a >> c;
+
+    int h2, a2;
+    cin >> h2 >> a2;
+    
+    vi ops;
+
+    while (h2 > 0) {
+        if (h2 <= a) {
+            ops.push_back(0);
+            h2 = 0;
+            continue;
+        }
+
+        if (a2 >= h) {
+            h += c;
+            h -= a2;
+            ops.push_back(1);
+            continue;
+        }
+
+        ops.push_back(0);
+        h2 -= a;
+        h -= a2;
+    }
+
+    cout << ops.size() << '\n';
+    repv(i, ops) {
+        cout << (i ? "HEAL\n" : "STRIKE\n");
+    }
+}

Educational Codeforces Round 34 (Rated for Div. 2)/C. Boxes Packing.cpp

@@ -0,0 +1,114 @@
+/* Problem URL: https://codeforces.com/contest/903/problem/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;
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int n;
+    cin >> n;
+
+    map<ll, int> var;
+    int v = 0;
+
+    vl a(n);
+
+    repv(i, a) {
+        cin >> i;
+        var[i] = 0;
+    }
+
+    repv(i, var) {
+        i.second = v;
+        v++;
+    }
+
+    vi count(var.size());
+
+    repv(i, a) {
+        count[var[i]]++;
+    }
+
+    nrep(i, 1, count.size()) {
+        int minimal = min(count[i], count[i - 1]);
+        count[i] += count[i - 1];
+        count[i] -= minimal;
+    }
+    
+    cout << count.back() << '\n';
+}

Educational Codeforces Round 34 (Rated for Div. 2)/D. Almost Difference.cpp

@@ -0,0 +1,170 @@
+/* Problem URL: https://codeforces.com/contest/903/problem/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;
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+#define int long long
+
+    int n;
+    cin >> n;
+
+    map<ll, int> var;
+    int v = 0;
+
+    vl a(n);
+    repv(i, a) {
+        cin >> i;
+        var[i] = 0;
+    }
+
+    vl inv(var.size());
+    repv(i, var) {
+        i.second = v;
+        inv[v] = i.first;
+        v++;
+    }
+
+    int size = v;
+    if (size > 1) {
+        size = 1 << (32 - __builtin_clz(size - 1));
+    }
+
+    V<pair<int, ll>> seg(size * 2);
+
+    auto update = [&](int i) {
+        i += size;
+        seg[i].first++;
+        seg[i].second += inv[i - size];
+
+        for (i >>= 1; i > 0; i >>= 1) {
+            seg[i] = {seg[i * 2].first + seg[i * 2 + 1].first, seg[i * 2].second + seg[i * 2 + 1].second};
+        }
+    };
+
+    function<pair<int, ll>(int, int, int, int, int)> query = [&](int i, int l, int r, int tl, int tr) -> pair<int, ll> {
+        if (l > tr || r < tl) {
+            return {0, 0};
+        }
+
+        if (l >= tl && r <= tr) {
+            return seg[i];
+        }
+
+        int mid = (l + r) >> 1;
+
+        auto ans1 = query(i * 2, l, mid, tl, tr);
+        auto ans2 = query(i * 2 + 1, mid + 1, r, tl, tr);
+
+        return {ans1.first + ans2.first, ans1.second + ans2.second};
+    };
+
+    __int128 ans = 0;
+
+    rep(i, n) {
+        int act = var[a[i]];
+        int upper = act + 1 + var.count(a[i] + 1);
+        int lower = act - 1 - var.count(a[i] - 1);
+
+        auto tmp = query(1, 0, size - 1, upper, v - 1);
+        ans += (__int128)tmp.first * a[i] - tmp.second;
+        
+        tmp = query(1, 0, size - 1, 0, lower);
+        ans += (__int128)tmp.first * a[i] - tmp.second;
+
+        update(act);
+    }
+
+    bool isneg = ans < 0;
+    bool iszero = ans == 0;
+
+    if (isneg) {
+        ans = -ans;
+    }
+
+    string act;
+    while (ans > 0) {
+        act.push_back((ans % 10) + '0');
+        ans /= 10;
+    }
+
+    reverse(all(act));
+
+    cout << (isneg ? "-" : "") << (iszero ? "0" : "") << act << '\n';
+}

Educational Codeforces Round 34 (Rated for Div. 2)/E. Swapping Characters.cpp

@@ -0,0 +1,188 @@
+/* Problem URL: https://codeforces.com/contest/903/problem/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;
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int n, k;
+    cin >> k >> n;
+
+    V<string> fds(k);
+    cin >> fds;
+
+    vi diffs;
+
+    int other = 0;
+
+    vi c1(26);
+    rep(i, n) {
+        c1[fds[0][i] - 'a']++;
+    }
+
+    nrep(i, 1, k) {
+        vi c2(26);
+        rep(j, n) {
+            if (fds[0][j] != fds[i][j]) {
+                diffs.push_back(j);
+            }
+            c2[fds[i][j] - 'a']++;
+        }
+
+        if (c1 != c2) {
+            cout << "-1\n";
+            return 0;
+        }
+
+        if (!diffs.empty()) {
+            other = i;
+            break;
+        }
+    }
+
+    if (diffs.empty()) {
+        swap(fds[0][0], fds[0][1]);
+        cout << fds[0] << '\n';
+        return 0;
+    }
+
+    if (diffs.size() > 4) {
+        cout << "-1\n";
+        return 0;
+    }
+
+    string now = fds[0];
+    auto test = [&]() {
+        rep(i, diffs.size()) {
+            rep(j, n) {
+                if (diffs[i] == j) {
+                    continue;
+                }
+                swap(now[diffs[i]], now[j]);
+
+                auto diff = [&](string &a, string &b) {
+                    vi count(26);
+                    bool lmao = false;
+
+                    int ans = 0;
+                    rep(i, n) {
+                        count[a[i] - 'a']++;
+                        lmao = lmao || count[a[i] - 'a'] >= 2;
+                        if (a[i] != b[i]) {
+                            ans++;
+                        }
+                    }
+
+                    return ans == 2 || (ans == 0 && lmao);
+                };
+
+                bool pos = true;
+
+                rep(l, k) {
+                    int d = diff(now, fds[l]);
+                    if (!diff(now, fds[l])) {
+                        pos = false;
+                        break;
+                    }
+                }
+
+                if (pos) {
+                    return true;
+                }
+
+                swap(now[diffs[i]], now[j]);
+            }
+        }
+
+        return false;
+    };
+
+    if (test()) {
+        cout << now << '\n';
+        return 0;
+    }
+
+    now = fds[other];
+
+    if (test()) {
+        cout << now << '\n';
+        return 0;
+    }
+
+    cout << "-1\n";
+}