P3469 [POI2008]BLO-Blockade

https://www.luogu.com.cn/record/87072207

Luogu/P3469/P3469.cpp

@@ -0,0 +1,77 @@
+#include <iostream>
+#include <utility>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e5 + 5;
+
+int n, m;
+long long ans[N];
+std::vector<int> g[N];
+int root, cnt, dfn[N], low[N], siz[N];
+bool cut[N];
+
+void tarjan(int u) {
+    dfn[u] = low[u] = ++cnt;
+    siz[u] = 1;
+
+    bool flag = false;
+    int sum = 0;
+
+    for (int v : g[u]) {
+        if (!dfn[v]) {
+            tarjan(v);
+            low[u] = std::min(low[u], low[v]);
+            siz[u] += siz[v];
+
+            if (dfn[u] <= low[v]) {
+                if (u != root || flag) {
+                    cut[u] = true;
+                    sum += siz[v];
+                    ans[u] += static_cast<long long>(n - siz[v]) * siz[v];
+                } else {
+                    flag = true;
+                }
+            }
+        } else {
+            low[u] = std::min(low[u], dfn[v]);
+        }
+    }
+
+    if (cut[u]) {
+        ans[u] += static_cast<long long>(n - sum - 1) * (sum + 1)
+                + n - 1;
+    } else {
+        ans[u] = 2 * (n - 1);
+    }
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m;
+
+    for (int i = 1, u, v; i <= m; i++) {
+        cin >> u >> v;
+
+        g[u].emplace_back(v);
+        g[v].emplace_back(u);
+    }
+
+    for (int i = 1; i <= n; i++) {
+        if (!dfn[i]) {
+            root = i;
+            tarjan(i);
+        }
+    }
+
+    for (int i = 1; i <= n; i++) {
+        cout << ans[i] << endl;
+    }
+
+    return 0;
+}