杭电 1874 畅通工程续

题目地址：http://acm.hdu.edu.cn/showproblem.php?pid=1874

　　本题最短路问题，我用的是dijkstra算法，这题不难，但是一开始以为不会遇到重边的问题，所以WA了一次！

#include <stdio.h>
#define MAXN 200
#define INF 100000
int mat[MAXN][MAXN];
int min[MAXN];
void Dijkstra(int n, int s)
{
int v[MAXN], i, j, k;
for( i = 0; i < n; i++ )
v[i] = 0, min[i] = INF;
for( min[s] = 0, j = 0; j < n; j++ )
{
for( k = -1, i = 0; i < n; i++ )
if( (!v[i]) && ((k == -1)||(min[i] < min[k])) )
k = i;
for( v[k] = 1, i = 0; i < n; i++ )
if( (!v[i]) && (min[k] + mat[k][i] < min[i]) )
min[i] = min[k] + mat[k][i];

}
}
int main()
{
int n, m, i, j, k, s, t, temp;
while(scanf( "%d%d", &n,&m ) != EOF)
{
for( i = 0; i < n; i++ )
for( j = 0; j < n; j++ )
mat[i][j] = INF;
/*for( i = 0; i < n; i++ )
{
for( j = 0; j < n; j++ )
printf("%d ",mat[i][j]);
printf("\n");
}
printf("\n\n");*/        for( k = 0; k < m; k++ )
{
scanf( "%d%d%d", &i, &j, &temp );
if( temp < mat[i][j] )
mat[j][i] = mat[i][j] = temp;
}
/*for( i = 0; i < n; i++ )
{
for( j = 0; j < n; j++ )
printf("%d ",mat[i][j]);
printf("\n");
}*/
scanf( "%d%d", &s, &t );
Dijkstra(n,s);
/*for( i = 0; i < n; i++ )
{
printf("%d ",min[i]);
}
printf( "\n" );
for( i = 0; i < n; i++ )
{
printf("%d ",pre[i]);
}
printf( "\n" );*/
if( min[t] == INF )
printf( "-1\n" );
else
printf("%d\n",min[t]);

}
return 0;
}

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