C++代码

#include<iostream>
#include<algorithm>
#include<cstring>

using namespace std;

const int N=510;

int n,m;
int g[N][N];
int dist[N];
bool vis[N];

int dijstra()
{
    memset(dist,0x3f3f3f3f,sizeof dist);
    dist[1]=0;

    for(int i=1;i<=n;i++)
    {
        int t=-1;
        for(int j=1;j<=n;j++)
        {
            if(!vis[j]&&(t==-1||dist[t]>dist[j]))
            {
                t=j;
            }
        }
        vis[t]=true;

        for(int j=1;j<=n;j++)
        {
            dist[j]=min(dist[j],dist[t]+g[t][j]);
        }
    }

    if(dist[n]==0x3f3f3f3f) return -1;
    return dist[n];
}//dijstra

int main(void)
{
    scanf("%d%d",&n,&m);
    memset(g,0x3f3f3f3f,sizeof g);

    while(m--)
    {
        int a,b,c;
        scanf("%d%d%d",&a,&b,&c);
        g[a][b]=min(g[a][b],c);
    }

    int res=dijstra();
    printf("%d\n",res);

    return 0;
}