[HDU-1233]还是畅通工程

基础最小生成树。

#include <cstdio>
#include <cstring>
#include <algorithm>
#define maxn 100 + 5
#define inf 100000
using namespace std;
int graph[maxn][maxn];
int path[maxn];
int cost[maxn];
int prim(int n)
{
    int ans = 0;
    int minid = 0;
    for (int i = 1; i <= n; i++)
        path[i] = i;
    for (int i = 1; i <= n; i++)
        cost[i] = graph[1][i];
    cost[1] = 0;
    for (int i = 0; i < n-1; i++)
    {
        int mincost = inf;
        for (int j = 1; j <=n; j++)
        {
            if (cost[j] != 0 && cost[j] < mincost)
            {
                mincost = cost[j];
                minid = j;
               // printf("%d %d
", j, mincost);
            }
        }
        //printf("%d
", mincost);
        cost[minid] = 0;
        ans += mincost;
        //printf ("%d
", ans);
        for (int i = 1; i <= n; i++)
        {
            //printf ("%d %d", cost[i], cost[minid] + graph[minid][i]);
            if (cost[i] > cost[minid] + graph[minid][i])
            {
                cost[i] = cost[minid] + graph[minid][i];
                //printf ("%d", cost[i]);
                path[i] = minid;
            }

        }
    }
    return ans;

}
int main()
{
    int n, m;
    while (scanf("%d", &n) && n)
    {
        fill(graph[0], graph[0] + maxn*maxn, inf);
        for (int i = 0; i < n*(n-1)/2; i++)
        {
            int temp1, temp2, temp3;
            scanf("%d %d %d", &temp1, &temp2, &temp3);
            graph[temp1][temp2] = temp3;
            graph[temp2][temp1] = temp3;

        }
        int ans = prim(n);
        printf("%d
", ans);
    }

    return 0;
}