08-图7 公路村村通

#include <stdio.h>#define MAXINT 0x7fffffff#define Max 1001int Graph[Max][Max];int Prim(int N);void DFS(int N, int i, int *Visited);int main(int argc, char const *argv[]){// freopen("test.txt", "r", stdin);int N, M;scanf("%d %d", &N, &M);for (int i = 1; i <= N; i++){for (int j = 1; j <= N; j++){Graph[i][j] = Graph[j][i] = MAXINT;}}for (int i = 1; i <= M; i++){int c1, c2, budget;scanf("%d %d %d", &c1, &c2, &budget);Graph[c1][c2] = Graph[c2][c1] = budget;}for (int i = 1; i <= N; i++)Visited[i] = 0;DFS(N, 1, Visited);int flag = 1;int Visited[N+1];for (int j = 1; j <= N; j++){if (Visited[j] == 0)flag = 0;}if (flag){int ans = Prim(N);printf("%d", ans);}elseprintf("-1");return 0;}void DFS(int N, int i, int *Visited){Visited[i] = 1;for (int j = 1; j <= N; j++){if (Visited[j] == 0 && Graph[i][j] != MAXINT){DFS(N, j, Visited);}}}int Prim(int N){int MST[N+1], dist[N+1], count = 0, sum = 0;for (int i = 0; i <= N; i++)MST[i] = 0;for (int i = 1; i <= N; i++)dist[i] = Graph[1][i];dist[1] = 0;while(1){int mindist = MAXINT, v = -1;for (int i = 1; i <= N; i++){if (MST[i] == 0 && dist[i] < mindist){v = i;mindist = dist[i];}}if (v == -1)break;MST[v] = 1, dist[v] = 0;sum += mindist, count++;for (int i = 1; i <= N; i++){if (MST[i] == 0 && Graph[v][i] < dist[i])dist[i] = Graph[v][i];}}if (count < N)return -1;elsereturn sum;}