Petrozavodsk Winter 2021. Day 8. Belarusian SU Contest

Author: Macesuted

QOJ/1085.cpp

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+/**
+ * @file 1085.cpp
+ * @author Macesuted (i@macesuted.moe)
+ * @date 2026-01-24
+ *
+ * @copyright Copyright (c) 2026
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#define endl '\n'
+
+#define maxn 1000005
+#define maxlgn 25
+#define mod 998244353
+
+int64_t f[maxn], g[maxlgn];
+int lg2[maxn];
+
+void solve(void) {
+    int n;
+    cin >> n;
+
+    f[1] = g[0] = 1;
+    int64_t sum = 2;
+    for (int i = 2; i <= n; i++) {
+        f[i] = sum;
+        for (int j = 0; j < lg2[i]; j++)
+            if (i >> j & 1) f[i] = (f[i] + mod - g[j]) % mod;
+        g[lg2[i]] = (g[lg2[i]] + f[i]) % mod, sum = (sum + f[i]) % mod;
+    }
+
+    cout << (sum + mod - 1) % mod << endl;
+
+    return;
+}
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+
+    for (int i = 2; i < maxn; i++) lg2[i] = lg2[i >> 1] + 1;
+
+    int _ = 1;
+    while (_--) solve();
+
+    return 0;
+}

QOJ/1092.cpp

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+/**
+ * @file 1092.cpp
+ * @author Macesuted (i@macesuted.moe)
+ * @date 2026-01-24
+ *
+ * @copyright Copyright (c) 2026
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#define endl '\n'
+
+#define maxn 300005
+
+vector<int> graph[maxn];
+int col[maxn], cnt[3];
+
+void dfs(int p, int c) {
+    cnt[col[p] = c]++;
+    for (auto q : graph[p])
+        if (!col[q]) dfs(q, 3 - c);
+    return;
+}
+
+void solve(void) {
+    int n, m;
+    cin >> n >> m;
+    for (int i = 1, x, y; i <= m; i++) cin >> x >> y, graph[x].push_back(y), graph[y].push_back(x);
+
+    int ans = 0;
+    for (int i = 1; i <= n; i++)
+        if (!col[i]) {
+            cnt[1] = cnt[2] = 0;
+            dfs(i, 1);
+            ans += min(cnt[1], cnt[2]);
+        }
+
+    for (int i = 1; i <= n; i++)
+        for (auto j : graph[i])
+            if (col[i] == col[j]) return cout << -1 << endl, void();
+
+    cout << max(1, ans) << endl;
+
+    return;
+}
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+
+    int _ = 1;
+    while (_--) solve();
+
+    return 0;
+}