【模板】SPFA

指路洛谷

#include<iostream>
#include<sstream>
#include<cstring>
#include<cstdio>
#include<queue>
using namespace std;
const long long INF=2147483647;
int s,N,n,last[500005],dis[500005],vis[500005];
struct node{
    int to,val,next;
}a[500005];
int add(int U,int V,int Edge){
    a[++n].to=V;
    a[n].val=Edge;
    a[n].next=last[U];
    last[U]=n;
    return 0;
}
int SPFA(){
    queue<int> q;
    q.push(s); 
    for(int i=1;i<=N;i++) dis[i]=INF;
    vis[s]=1;
    dis[s]=0;
    while(!q.empty()){
        int u=q.front();
        q.pop();
        vis[u]=0;
        for(int i=last[u];i;i=a[i].next){
            int v=a[i].to;
            if(dis[u]==INF||a[i].val==INF) continue;
            if(dis[v]>dis[u]+a[i].val){
                dis[v]=dis[u]+a[i].val;
                if(vis[v]==1) continue;
                vis[v]=1;
                q.push(v);
            }
        }
    }
    return 0;
}
int main(){
    int m;
    memset(dis,INF,sizeof(dis));
    memset(vis,0,sizeof(vis));
    scanf("%d%d%d",&N,&m,&s);
    for(int i=1;i<=m;i++){
        int u,v,edge;
        scanf("%d%d%d",&u,&v,&edge);
        add(u,v,edge);
    }
    SPFA();
    for(int i=1;i<=N;i++) printf("%d ",dis[i]);
    return 0;
}

标签：val,int,vis,SPFA,include,500005,模板,dis
来源： https://www.cnblogs.com/latent-Lin/p/13927490.html