POJ 2485 Highways

解题思路:Prim算法求解最小生成树，

#include<iostream>
using namespace std;

#define MaxNum 1e8

int main()
{
    int m, n, min, start, tempS, MinMax;
    int edge[505][505];
    int dist[505];
    int path[505];
    bool visited[505];
    scanf("%d", &m);
    while (m--)
    {
        scanf("%d", &n);

        dist[0] = 0;
        start = 0;
        path[0] = 0;

        fill(&dist[1], &dist[n], MaxNum);
        fill(&path[1], &path[n], -1);
        memset(visited, 0, sizeof(bool) * 505);

        for (int i = 0; i < n; i++)
            for (int j = 0; j < n; j++)
                 scanf("%d", &edge[i][j]);

        while (start != -1)
        {
            visited[start] = true;
            tempS = -1;
            min = MaxNum;

            for (int i = 0; i < n; i++)
            {
                if (!visited[i])
                {
                    if (dist[i] > edge[start][i])
                    {
                        dist[i] = edge[start][i];
                        path[i] = start;
                    }
                    if (min > dist[i])
                    {
                        min = dist[i];
                        tempS = i;
                    }
                }
            }
            start = tempS;
        }
        MinMax = 0;
        for (int i = 0; i < n; i++)
            if (MinMax < edge[path[i]][i])
                MinMax = edge[path[i]][i];
        printf("%d\n", MinMax);
    }
    return 0;
}