849. Dijkstra求最短路 I

https://www.acwing.com/problem/content/submission/code_detail/6501777/

AcWing/849/849.cpp

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+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n, m, x, y, z, g[505][505], dist[505];
+bool st[505];
+
+int diskstra() {
+    memset(dist, 0x3f, sizeof(dist));
+    dist[1] = 0;
+    for (int i = 0; i < n - 1; i++) {
+        int t = -1;
+        for (int j = 1; j <= n; j++) {
+            if (!st[j] && (t == -1 || dist[t] > dist[j])) {
+                t = j;
+            }
+        }
+        for (int j = 1; j <= n; j++) {
+            dist[j] = min(dist[j], dist[t] + g[t][j]);
+        }
+        st[t] = true;
+    }
+    return dist[n] == 0x3f3f3f3f ? -1 : dist[n];
+}
+
+int main() {
+    cin >> n >> m;
+    for (int i = 1; i <= n; i++) {
+        for (int j = 1; j <= n; j++) {
+            g[i][j] = i == j ? 0 : 0x3f3f3f3f;
+        }
+    }
+    for (int i = 1; i <= m; i++) {
+        cin >> x >> y >> z;
+        g[x][y] = min(g[x][y], z);
+    }
+    cout << diskstra() << endl;
+    return 0;
+}