'commit'

TangDou/AcWing_TiGao/T3/MinialSpanningTree/1140_Prim.cpp

@@ -0,0 +1,42 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+const int N = 110;
+const int INF = 0x3f3f3f3f;
+
+int n;
+int g[N][N];
+int dis[N];
+bool st[N];
+int res;
+
+int prim() {
+    memset(dis, 0x3f, sizeof dis);
+    dis[1] = 0;
+
+    for (int i = 0; i < n; i++) { // 迭代n次
+        int t = -1;
+        for (int j = 1; j <= n; j++)
+            if (!st[j] && (t == -1 || dis[t] > dis[j])) t = j;
+        if (i && dis[t] == INF) return INF; // 非连通图，没有最小生成树
+        if (i) res += dis[t];
+        for (int j = 1; j <= n; j++)
+            if (!st[j] && g[t][j] < dis[j]) {
+                dis[j] = g[t][j];
+            }
+        st[t] = true;
+    }
+    return res;
+}
+
+int main() {
+    cin >> n;
+    // 初始化
+    memset(g, 0x3f, sizeof g);
+
+    for (int i = 1; i <= n; i++)
+        for (int j = 1; j <= n; j++)
+            cin >> g[i][j]; // 有向图
+    cout << prim() << endl;
+    return 0;
+}