mirror of
https://git.sb/baoshuo/OI-codes.git
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86 lines
1.7 KiB
C++
86 lines
1.7 KiB
C++
#include <iostream>
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#include <stack>
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#include <vector>
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using std::cin;
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using std::cout;
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using std::endl;
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const int N = 3005;
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int n, p, x, r, u, v, ans, a[N], w[N];
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std::vector<int> g[N];
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// Tarjan
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int cnt, dfn[N], low[N];
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int scc_cnt, id[N];
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int din[N];
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std::stack<int> st;
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bool vis[N];
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void tarjan(int u) {
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dfn[u] = low[u] = ++cnt;
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st.push(u);
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vis[u] = true;
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for (int v : g[u]) {
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if (!dfn[v]) {
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tarjan(v);
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low[u] = std::min(low[u], low[v]);
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} else if (vis[v]) {
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low[u] = std::min(low[u], dfn[v]);
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}
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}
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if (low[u] == dfn[u]) {
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scc_cnt++;
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int v;
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do {
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v = st.top();
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st.pop();
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vis[v] = false;
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id[v] = scc_cnt;
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w[scc_cnt] = std::min(w[scc_cnt], a[v]);
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} while (v != u);
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}
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}
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int main() {
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std::fill(a, a + N, 0x7fff);
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std::fill(w, w + N, 0x7fff);
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cin >> n >> p;
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for (int i = 1; i <= p; i++) {
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cin >> x >> a[x];
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}
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cin >> r;
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for (int i = 1; i <= r; i++) {
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cin >> u >> v;
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g[u].push_back(v);
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}
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for (int i = 1; i <= n; i++) {
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if (!dfn[i] && a[i] != 0x7fff) {
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tarjan(i);
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}
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}
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for (int i = 1; i <= n; i++) {
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if (!dfn[i]) {
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cout << "NO" << endl
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<< i << endl;
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exit(0);
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}
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}
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for (int i = 1; i <= n; i++) {
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for (int v : g[i]) {
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if (id[i] != id[v]) {
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din[id[v]]++;
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}
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}
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}
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for (int i = 1; i <= scc_cnt; i++) {
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if (!din[i]) {
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ans += w[i];
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}
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}
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cout << "YES" << endl
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<< ans << endl;
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return 0;
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}
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