From 14338f0f108166a3cc75cc28db4307993eb57baf Mon Sep 17 00:00:00 2001
From: Baoshuo <i@baoshuo.ren>
Date: Sun, 2 Jan 2022 11:27:07 +0800
Subject: [PATCH] =?UTF-8?q?P1262=20=E9=97=B4=E8=B0=8D=E7=BD=91=E7=BB=9C?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

R66133558
---
 Luogu/P1262/P1262.cpp | 85 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)
 create mode 100644 Luogu/P1262/P1262.cpp

diff --git a/Luogu/P1262/P1262.cpp b/Luogu/P1262/P1262.cpp
new file mode 100644
index 00000000..a9abd928
--- /dev/null
+++ b/Luogu/P1262/P1262.cpp
@@ -0,0 +1,85 @@
+#include <iostream>
+#include <stack>
+#include <vector>
+
+using std::cin;
+using std::cout;
+using std::endl;
+
+const int N = 3005;
+
+int n, p, x, r, u, v, ans, a[N], w[N];
+std::vector<int> g[N];
+
+// Tarjan
+int cnt, dfn[N], low[N];
+int scc_cnt, id[N];
+int din[N];
+std::stack<int> st;
+bool vis[N];
+
+void tarjan(int u) {
+    dfn[u] = low[u] = ++cnt;
+    st.push(u);
+    vis[u] = true;
+    for (int v : g[u]) {
+        if (!dfn[v]) {
+            tarjan(v);
+            low[u] = std::min(low[u], low[v]);
+        } else if (vis[v]) {
+            low[u] = std::min(low[u], dfn[v]);
+        }
+    }
+    if (low[u] == dfn[u]) {
+        scc_cnt++;
+        int v;
+        do {
+            v = st.top();
+            st.pop();
+            vis[v] = false;
+            id[v] = scc_cnt;
+            w[scc_cnt] = std::min(w[scc_cnt], a[v]);
+        } while (v != u);
+    }
+}
+
+int main() {
+    std::fill(a, a + N, 0x7fff);
+    std::fill(w, w + N, 0x7fff);
+    cin >> n >> p;
+    for (int i = 1; i <= p; i++) {
+        cin >> x >> a[x];
+    }
+    cin >> r;
+    for (int i = 1; i <= r; i++) {
+        cin >> u >> v;
+        g[u].push_back(v);
+    }
+    for (int i = 1; i <= n; i++) {
+        if (!dfn[i] && a[i] != 0x7fff) {
+            tarjan(i);
+        }
+    }
+    for (int i = 1; i <= n; i++) {
+        if (!dfn[i]) {
+            cout << "NO" << endl
+                 << i << endl;
+            exit(0);
+        }
+    }
+    for (int i = 1; i <= n; i++) {
+        for (int v : g[i]) {
+            if (id[i] != id[v]) {
+                din[id[v]]++;
+            }
+        }
+    }
+    for (int i = 1; i <= scc_cnt; i++) {
+        if (!din[i]) {
+            ans += w[i];
+        }
+    }
+    cout << "YES" << endl
+         << ans << endl;
+    return 0;
+}