Good Bye 2025

Author: Macesuted

Codeforces/2178A.cpp

@@ -0,0 +1,49 @@
+/**
+ * @file 2178A.cpp
+ * @author Macesuted ([email protected])
+ * @date 2025-12-27
+ *
+ * @copyright Copyright (c) 2025
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#ifndef LOCAL
+#define endl '\n'
+#endif
+
+bool mem1;
+
+void solve(void) {
+    string s;
+    cin >> s;
+
+    int cntN = 0;
+    for (auto c : s) cntN += (c == 'N');
+
+    int cntY = s.size() - cntN;
+
+    cout << (cntY <= 1 ? "YES" : "NO") << endl;
+
+    return;
+}
+
+bool mem2;
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+#ifdef LOCAL
+    cerr << "Memory Cost: " << abs(&mem1 - &mem2) / 1024. / 1024. << "MB" << endl;
+#endif
+
+    int _ = 1;
+    cin >> _;
+    while (_--) solve();
+
+#ifdef LOCAL
+    cerr << "Time Cost: " << clock() * 1000. / CLOCKS_PER_SEC << "MS" << endl;
+#endif
+    return 0;
+}

Codeforces/2178B.cpp

@@ -0,0 +1,53 @@
+/**
+ * @file 2178B.cpp
+ * @author Macesuted ([email protected])
+ * @date 2025-12-27
+ *
+ * @copyright Copyright (c) 2025
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#ifndef LOCAL
+#define endl '\n'
+#endif
+
+bool mem1;
+
+void solve(void) {
+    string s;
+    cin >> s;
+
+    int f[2] = {int(1e9), s[0] == 'u'};
+
+    for (auto c : s.substr(1)) {
+        if (c == 's')
+            f[1] = min(f[0], f[1]), f[0] = 1e9;
+        else
+            tie(f[0], f[1]) = make_pair(f[1], 1 + min(f[0], f[1]));
+    }
+
+    cout << f[1] << endl;
+
+    return;
+}
+
+bool mem2;
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+#ifdef LOCAL
+    cerr << "Memory Cost: " << abs(&mem1 - &mem2) / 1024. / 1024. << "MB" << endl;
+#endif
+
+    int _ = 1;
+    cin >> _;
+    while (_--) solve();
+
+#ifdef LOCAL
+    cerr << "Time Cost: " << clock() * 1000. / CLOCKS_PER_SEC << "MS" << endl;
+#endif
+    return 0;
+}

Codeforces/2178C.cpp

@@ -0,0 +1,60 @@
+/**
+ * @file 2178C.cpp
+ * @author Macesuted ([email protected])
+ * @date 2025-12-27
+ *
+ * @copyright Copyright (c) 2025
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#ifndef LOCAL
+#define endl '\n'
+#endif
+
+bool mem1;
+
+#define maxn 200005
+
+int a[maxn];
+
+void solve(void) {
+    int n;
+    cin >> n;
+    for (int i = 1; i <= n; i++) cin >> a[i];
+
+    int64_t cur = 0;
+    for (int i = 2; i <= n; i++) cur -= a[i];
+
+    int64_t ans = cur;
+
+    for (int i = 2; i <= n; i++) {
+        cur += a[i];
+        cur += (i == 2 ? a[1] : abs(a[i - 1]));
+        ans = max(ans, cur);
+    }
+
+    cout << ans << endl;
+
+    return;
+}
+
+bool mem2;
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+#ifdef LOCAL
+    cerr << "Memory Cost: " << abs(&mem1 - &mem2) / 1024. / 1024. << "MB" << endl;
+#endif
+
+    int _ = 1;
+    cin >> _;
+    while (_--) solve();
+
+#ifdef LOCAL
+    cerr << "Time Cost: " << clock() * 1000. / CLOCKS_PER_SEC << "MS" << endl;
+#endif
+    return 0;
+}

Codeforces/2178D.cpp

@@ -0,0 +1,72 @@
+/**
+ * @file 2178D.cpp
+ * @author Macesuted ([email protected])
+ * @date 2025-12-27
+ *
+ * @copyright Copyright (c) 2025
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#ifndef LOCAL
+#define endl '\n'
+#endif
+
+bool mem1;
+
+#define maxn 200005
+
+using pii = pair<int, int>;
+
+int a[maxn];
+int id[maxn];
+
+void solve(void) {
+    int n, m;
+    cin >> n >> m;
+    for (int i = 1; i <= n; i++) cin >> a[i];
+
+    if (m * 2 > n) return cout << -1 << endl, void();
+
+    for (int i = 1; i <= n; i++) id[i] = i;
+    sort(id + 1, id + n + 1, [&](int x, int y) { return a[x] < a[y]; });
+    sort(a + 1, a + n + 1);
+
+    vector<pii> ans;
+
+    if (m > 0) {
+        for (int i = 1; i < m; i++) ans.emplace_back(n - i + 1, i);
+        for (int i = m; i + 1 < n - m + 1; i++) ans.emplace_back(i, i + 1);
+        ans.emplace_back(n - m + 1, n - m);
+    } else {
+        int h = a[n], p = 1;
+        while (a[n - 1] < h && p < n - 1) ans.emplace_back(p, n), h -= a[p++];
+        if (a[n - 1] < h) return cout << -1 << endl, void();
+        while (p < n) ans.emplace_back(p, p + 1), p++;
+    }
+
+    cout << ans.size() << endl;
+    for (auto [x, y] : ans) cout << id[x] << ' ' << id[y] << endl;
+
+    return;
+}
+
+bool mem2;
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+#ifdef LOCAL
+    cerr << "Memory Cost: " << abs(&mem1 - &mem2) / 1024. / 1024. << "MB" << endl;
+#endif
+
+    int _ = 1;
+    cin >> _;
+    while (_--) solve();
+
+#ifdef LOCAL
+    cerr << "Time Cost: " << clock() * 1000. / CLOCKS_PER_SEC << "MS" << endl;
+#endif
+    return 0;
+}

Codeforces/2178E.cpp

@@ -0,0 +1,69 @@
+/**
+ * @file 2178E.cpp
+ * @author Macesuted ([email protected])
+ * @date 2025-12-27
+ *
+ * @copyright Copyright (c) 2025
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+bool mem1;
+
+int lg2(int64_t x) {
+    int cnt = 0;
+    while (!(x & 1)) x >>= 1, cnt++;
+    return cnt;
+}
+
+int64_t query(int l, int r) {
+    cout << "? " << l << ' ' << r << endl;
+    int64_t ret;
+    cin >> ret;
+    return ret;
+}
+
+int solve(int l, int r, int k) {
+    if (l == r) return k;
+
+    int64_t tar = (int64_t)1 << (k - 1);
+
+    int xl = l, xr = r;
+    while (xl + 1 < xr) {
+        int mid = (xl + xr) >> 1;
+        (query(l, mid) <= tar ? xl : xr) = mid;
+    }
+
+    return xr - l <= r - xl ? solve(l, xl, k - 1) : solve(xr, r, k - 1);
+}
+
+void solve(void) {
+    int n;
+    cin >> n;
+
+    int k = solve(1, n, lg2(query(1, n)));
+
+    cout << "! " << ((int64_t)1 << k) << endl;
+
+    return;
+}
+
+bool mem2;
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+#ifdef LOCAL
+    cerr << "Memory Cost: " << abs(&mem1 - &mem2) / 1024. / 1024. << "MB" << endl;
+#endif
+
+    int _ = 1;
+    cin >> _;
+    while (_--) solve();
+
+#ifdef LOCAL
+    cerr << "Time Cost: " << clock() * 1000. / CLOCKS_PER_SEC << "MS" << endl;
+#endif
+    return 0;
+}

Codeforces/2178F.cpp

@@ -0,0 +1,85 @@
+/**
+ * @file 2178F.cpp
+ * @author Macesuted ([email protected])
+ * @date 2025-12-28
+ *
+ * @copyright Copyright (c) 2025
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#ifndef LOCAL
+#define endl '\n'
+#endif
+
+bool mem1;
+
+#define maxn 200005
+#define mod 998244353
+
+vector<vector<int>> graph;
+int siz[maxn];
+
+int64_t qpow(int64_t a, int64_t x) {
+    int64_t ans = 1;
+    while (x) {
+        if (x & 1) ans = ans * a % mod;
+        a = a * a % mod, x >>= 1;
+    }
+    return ans;
+}
+int64_t inv(int64_t a) { return qpow(a, mod - 2); }
+
+void dfs(int p, int pre = -1) {
+    siz[p] = 1;
+    for (auto q : graph[p])
+        if (q != pre) dfs(q, p), siz[p] += (siz[q] & 1) ? siz[q] : 0;
+    return;
+}
+
+void solve(void) {
+    int n;
+    cin >> n;
+    graph.clear(), graph.resize(n + 1);
+    for (int i = 1, x, y; i < n; i++) cin >> x >> y, graph[x].push_back(y), graph[y].push_back(x);
+
+    dfs(1);
+
+    vector<int> S;
+    for (int i = 2; i <= n; i++)
+        if (!(siz[i] & 1)) S.push_back(siz[i]);
+
+    if (S.empty()) return cout << 1 << endl, void();
+
+    int64_t ans = 0, mul = 1;
+    for (auto s : S) mul = mul * s % mod;
+    mul = mul * mul % mod * siz[1] % mod;
+
+    for (auto s : S) ans = (ans + mul * inv(s)) % mod;
+
+    for (int i = 1; i < (int)S.size(); i++) ans = ans * i % mod;
+
+    cout << ans << endl;
+
+    return;
+}
+
+bool mem2;
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+#ifdef LOCAL
+    cerr << "Memory Cost: " << abs(&mem1 - &mem2) / 1024. / 1024. << "MB" << endl;
+#endif
+
+    int _ = 1;
+    cin >> _;
+    while (_--) solve();
+
+#ifdef LOCAL
+    cerr << "Time Cost: " << clock() * 1000. / CLOCKS_PER_SEC << "MS" << endl;
+#endif
+    return 0;
+}