AcWing 849. Dijkstra求最短路 I

#include<iostream>
#include<cstring>
#include<algorithm>
using namespace std;

const int N=510,M=100010;

int h[N],e[M],ne[M],w[M],idx;
int state[N];
int dist[N];
int n,m;

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

void Dijkstra()
{
    memset(dist,0x3f,sizeof dist);
    dist[1]=0;
    for(int i=0;i<n;i++)
    {
        int t=-1;
        for(int j=1;j<=n;j++)
        {
            if(!state[j] && (t==-1 || dist[j]<dist[t]))
                t=j;
        }

        state[t]=1;

        for(int j=h[t];j!=-1;j=ne[j])
        {
            int i=e[j];
            dist[i]=min(dist[i],dist[t]+w[j]);
        }
    }


}


int main()
{
    memset(h,-1,sizeof h);
    cin>>n>>m;
    while(m--)
    {
        int a,b,w;
        cin>>a>>b>>w;
        add(a,b,w);
    }
    Dijkstra();
    if(dist[n]!=0x3f3f3f3f)
        cout<<dist[n];
    else
        cout<<"-1";
}