【模板】SPFA Dijkstra+Heap(priority_queue)

SPFA

#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
using namespace std;
const int M=500010;
const int N=100010;
struct E {int to,nxt,w;}edge[M];
queue<int>q;
bool vis[N];
int idx[N],tot=1;
int n,m,s,t,dis[N];
void addedge(int from,int to,int w){
    edge[tot].to=to;edge[tot].w=w;edge[tot].nxt=idx[from];idx[from]=tot++;
}
void SPFA(){
    q.push(s);vis[s]=1;
    memset(dis,127,sizeof(dis));
    dis[s]=0;
    while(!q.empty()){
        int x=q.front();q.pop();
        for(int t=idx[x];t;t=edge[t].nxt){
            E e=edge[t];
            if(dis[e.to]>dis[x]+e.w){
                dis[e.to]=dis[x]+e.w;
                if(!vis[e.to]){
                    vis[e.to]=1;
                    q.push(e.to);
                }
            }
        }
        vis[x]=0;
    }
}
int main(){
// freopen("in.txt","r",stdin);
// freopen("out.txt","w",stdout);
    scanf("%d%d%d%d",&n,&m,&s,&t);
    for(int i=1;i<=m;i++) {
        int x,y,w;
        scanf("%d%d%d",&x,&y,&w);
        addedge(x,y,w);
    }
    SPFA();
    printf("%d\n",dis[t]);
    return 0;
}

Dijkstra+优先级队列

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<queue>
#include<algorithm>
using namespace std;
const int N=100010;
const int M=500010;
struct E {int to,nxt,w;}edge[M];
struct P {
    int d,x;
    bool operator < (const P& p) const { return p.d<d; }
}tmp;
priority_queue<P>Q;
bool vis[N];
int dis[N];
int tot=1,idx[N];
int s,t,n,m;
void addedge(int from,int to,int w){
    edge[tot].to=to;edge[tot].w=w;edge[tot].nxt=idx[from];idx[from]=tot++;
}
void dijkstra(){
    memset(dis,127,sizeof(dis));
    memset(vis,0,sizeof(vis));
    tmp.d=0,tmp.x=s;
    dis[s]=0;
    Q.push(tmp);
    while(!Q.empty()){
        P p=Q.top();Q.pop();
        int x=p.x;int d=p.d;
        if(vis[x]) continue;vis[x]=1;
        for(int t=idx[x];t;t=edge[t].nxt){
            E e=edge[t];
            if(d+e.w<dis[e.to]){
                dis[e.to]=d+e.w;
                tmp.d=dis[e.to],tmp.x=e.to;
                Q.push(tmp);
            }
        }
    }
}
int main(){
// freopen("in.txt","r",stdin);
// freopen("out.txt","w",stdout);
    scanf("%d%d%d%d",&n,&m,&s,&t);
    for(int i=1;i<=m;i++){
        int x,y,w;
        scanf("%d%d%d",&x,&y,&w);
        addedge(x,y,w);
    }
    dijkstra();
    printf("%d\n",dis[t]);
    return 0;
}