【HDU1874】畅通工程续【dijkstra】

#include<stdio.h>
#include<string.h>
#define INF 0x3f3f3f
#define max 200+10
int dis[max],vis[max];
int m[max][max];
int city,road;
int s,e;
void dijkstra()
{
int i,j;
int minn;
int next;
memset(vis,0,sizeof(vis));
for( i=0; i<city; i++)
{
dis[i]=m[s][i];
}
vis[s]=1;
for(i=1; i<city; i++)
{
minn=INF;
for( j=0; j<city; j++)
{
if(vis[j]==0&&minn>dis[j])
{
minn=dis[j];
next=j;
}
}
vis[next]=1;
for(j=0; j<city; j++)
{
if(vis[j]==0&&dis[next]+m[next][j]<dis[j])
{
dis[j]=dis[next]+m[next][j];
}
}
}
if(dis[e]==INF)
printf("-1\n");
else
printf("%d\n",dis[e]);
}

int main()
{
int i,j,a,b,c;
while(~scanf("%d%d",&city,&road))
{
for( i=0; i<city; i++)
{
for( j=0; j<city; j++)
{
if(i==j)
m[i][j]=0;
else
m[i][j]=INF;
}
}
while(road--)
{
scanf("%d%d%d",&a,&b,&c);
if(m[a][b]>c)
{
m[a][b]=m[b][a]=c;
}

}
scanf("%d%d",&s,&e);
dijkstra();
}
return 0;
}