HDU1874 畅通工程续 单源最短路径

HDU1874 畅通工程续 单源最短路径

最简单的dijkstra应用，别的就不说了 题目链接： http://acm.hdu.edu.cn/showproblem.php?pid=1874

#include < stdio.h >
#include < string .h >
#define  MAXN 201
#define  MAX 999999
int  dist[MAXN][MAXN],x[MAXN];
int  main()
{
     int  n,m,i,j,t,s,d,a,b,time,min;
     while (scanf( " %d%d " , & n, & m) == 2 )
    {
         for (i = 0 ;i < n;i ++ )
        {
             for (j = 0 ;j < n;j ++ )
            {
                 if (i == j)
                    dist[i][j] = 0 ;
                 else
                    dist[i][j] = MAX;
            }
        }
         for (i = 0 ;i < m;i ++ )
        {
            scanf( " %d%d%d " , & a, & b, & time);
            dist[a][b] = dist[b][a] = time < dist[a][b] ? time:dist[a][b];
        }
        scanf( " %d%d " , & s, & d);
         for (i = 0 ;i < n;i ++ )
        x[i] = dist[s][i];
        dist[s][s] = 1 ;
        t = 0 ;
         while (t !=- 1 )
        {
            min =- 1 ;
            t =- 1 ;
             for (i = 0 ;i < n;i ++ )
             if (dist[i][i] == 0 && (min ==- 1 || x[i] < min))
            {
                min = x[i];
                t = i;
            }
             if (t !=- 1 )
            {
                dist[t][t] = 1 ;
                 for (i = 0 ;i < n;i ++ )
                 if (x[i] > x[t] + dist[t][i])
                {
                    x[i] = x[t] + dist[t][i];
                }
            }
        }
         if (x[d] < MAX)
            printf( " %d\n " ,x[d]);
         else
            printf( " -1\n " );
    }
     return   0 ;
}