850. Dijkstra求最短路 II

https://www.acwing.com/problem/content/submission/code_detail/6522838/

AcWing/850/850.cpp

@@ -0,0 +1,40 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n, m, u, v, w, dist[200005];
+vector<pair<int, int>> g[200005];
+bool st[200005];
+
+void dijkstra() {
+    memset(dist, 0x3f, sizeof(dist));
+    dist[1] = 0;
+    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> q;
+    q.push(make_pair(0, 1));
+    while (!q.empty()) {
+        auto t = q.top();
+        q.pop();
+        int tw = t.second;
+        int td = t.first;
+        if (st[tw]) continue;
+        for (auto i : g[tw]) {
+            int j = i.first;
+            if (dist[j] > td + i.second) {
+                dist[j] = td + i.second;
+                q.push(make_pair(dist[j], j));
+            }
+        }
+        st[tw] = true;
+    }
+}
+
+int main() {
+    cin >> n >> m;
+    for (int i = 1; i <= m; i++) {
+        cin >> u >> v >> w;
+        g[u].push_back(make_pair(v, w));
+    }
+    dijkstra();
+    cout << (dist[n] == 0x3f3f3f3f ? -1 : dist[n]) << endl;
+    return 0;
+}