P6770 [USACO05MAR]Checking an Alibi 不在场的证明

R54888422

Luogu/problem/P6770/P6770.cpp

@@ -0,0 +1,47 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int f, p, c, m, u, v, w, x, dist[505];
+bool vis[505];
+vector<pair<int, int>> g[505];
+priority_queue<int, vector<int>, greater<int>> ans;
+
+void dijkstra() {
+    memset(dist, 0x3f, sizeof(dist));
+    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> q;
+    dist[1] = 0;
+    q.push(make_pair(0, 1));
+    while (!q.empty()) {
+        auto t = q.top();
+        q.pop();
+        if (vis[t.second]) continue;
+        for (auto i : g[t.second]) {
+            if (dist[i.first] > t.first + i.second) {
+                dist[i.first] = t.first + i.second;
+                q.push(make_pair(dist[i.first], i.first));
+            }
+        }
+        vis[t.second] = true;
+    }
+}
+
+int main() {
+    cin >> f >> p >> c >> m;
+    for (int i = 1; i <= p; i++) {
+        cin >> u >> v >> w;
+        g[u].push_back(make_pair(v, w));
+        g[v].push_back(make_pair(u, w));
+    }
+    dijkstra();
+    for (int i = 1; i <= c; i++) {
+        cin >> x;
+        if (dist[x] <= m) ans.push(i);
+    }
+    cout << ans.size() << endl;
+    while (!ans.empty()) {
+        cout << ans.top() << endl;
+        ans.pop();
+    }
+    return 0;
+}