C++代码

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

using namespace std;

const int N=1.5e5+10;

typedef pair<int,int> PII;

int n,m;
int h[N],e[N],ne[N],w[N],idx;
int dist[N];
bool vis[N];

void add(int a,int b,int c)
{
    e[idx]=b,ne[idx]=h[a],h[a]=idx,w[idx]=c;
    idx++;
}//add

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

    priority_queue<PII,vector<PII>,greater<PII> > heap;
    heap.push({0,1});

    while(heap.size())
    {
        auto t=heap.top();
        heap.pop();

        int num=t.second,distance=t.first;

        if(vis[num]) continue;
        vis[num]=true;

        for(int i=h[num];i!=-1;i=ne[i])
        {
            int j=e[i];
            if(dist[j]>distance+w[i])
            {
                dist[j]=distance+w[i];
                heap.push({dist[j],j});
            }
        }
    }

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

int main(void)
{
    scanf("%d%d",&n,&m);
    memset(h,-1,sizeof h);

    while(m--)
    {
        int a,b,c;
        scanf("%d%d%d",&a,&b,&c);
        add(a,b,c);
    }

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

    return 0;
}