Educational Codeforces Round 189 (Rated for Div. 2)

Author: Macesuted

Codeforces/2225A.cpp

@@ -0,0 +1,44 @@
+/**
+ * @file 2225A.cpp
+ * @author Macesuted (i@macesuted.moe)
+ * @date 2026-04-21
+ *
+ * @copyright Copyright (c) 2026
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#ifndef LOCAL
+#define endl '\n'
+#endif
+
+bool mem1;
+
+void solve(void) {
+    int64_t x, y;
+    cin >> x >> y;
+    for (int64_t z = 2 * x; z < y; z += x)
+        if (y % z) return cout << "YES" << endl, void();
+    cout << "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/2225B.cpp

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+/**
+ * @file 2225B.cpp
+ * @author Macesuted (i@macesuted.moe)
+ * @date 2026-04-21
+ *
+ * @copyright Copyright (c) 2026
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#ifndef LOCAL
+#define endl '\n'
+#endif
+
+bool mem1;
+
+void solve(void) {
+    string s;
+    cin >> s;
+    int n = s.size();
+
+    int cnt = 0;
+    for (int i = 1; i < n; i++) cnt += s[i] == s[i - 1];
+
+    cout << (cnt <= 2 ? "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/2225C.cpp

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+/**
+ * @file 2225C.cpp
+ * @author Macesuted (i@macesuted.moe)
+ * @date 2026-04-21
+ *
+ * @copyright Copyright (c) 2026
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#ifndef LOCAL
+#define endl '\n'
+#endif
+
+bool mem1;
+
+void solve(void) {
+    int n;
+    cin >> n;
+    string s[2];
+    cin >> s[0] >> s[1];
+
+    int f = INT64_MAX, g = 0;
+    for (int i = 0; i < n; i++) {
+        int ng = g + (s[0][i] != s[1][i]);
+        if (i) ng = min(ng, f + (s[0][i - 1] != s[0][i]) + (s[1][i - 1] != s[1][i]));
+        f = g, g = ng;
+    }
+
+    cout << g << 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/2225D.cpp

@@ -0,0 +1,48 @@
+/**
+ * @file 2225D.cpp
+ * @author Macesuted (i@macesuted.moe)
+ * @date 2026-04-21
+ *
+ * @copyright Copyright (c) 2026
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#ifndef LOCAL
+#define endl '\n'
+#endif
+
+bool mem1;
+
+void solve(void) {
+    int64_t n, x;
+    cin >> n >> x;
+
+    __int128_t l[2] = {((x - 1) >> 2) + 2 - (((x - 1) & 3) < 3), ((x - 1) >> 2) + 1 - (((x - 1) & 3) < 1)},
+               r[2] = {((n >> 2) + 2 - ((n & 3) < 3)), (n >> 2) + 1 - ((n & 3) < 1)};
+    r[0] -= l[0], r[1] -= l[1];
+
+    cout << int64_t((l[0] * r[0] + l[1] * r[1]) % 998244353) << 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/2225G.cpp

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+/**
+ * @file 2225G.cpp
+ * @author Macesuted (i@macesuted.moe)
+ * @date 2026-04-21
+ *
+ * @copyright Copyright (c) 2026
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#ifndef LOCAL
+#define endl '\n'
+#endif
+
+bool mem1;
+
+int x[15];
+bool vis[5005];
+
+void solve(void) {
+    int n, m;
+    cin >> n >> m;
+    for (int i = 1; i <= m; i++) cin >> x[i];
+
+    int g = x[1];
+    for (int i = 2; i <= m; i++) g = gcd(g, x[i]);
+
+    if (g != 1) return cout << -1 << endl, void();
+
+    sort(x + 1, x + m + 1);
+
+    for (int i = 0; i < n; i++) vis[i] = false;
+
+    cout << 0, vis[0] = true;
+
+    for (int i = 1, p = 0; i < n; i++) {
+        int q = 0;
+        for (int j = n - 1; j > 0 && !q; j--)
+            if (!((j - p) % x[1]) && !vis[j]) q = j;
+
+        for (int i = 2; i <= m && !q; i++)
+            if (!vis[p + x[i]]) q = p + x[i];
+
+        cout << ' ' << (p = q), vis[p] = true;
+    }
+
+    cout << 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;
+}