https://www.luogu.org/problemnew/show/P3371
鉴于残暴的人喜欢卡SPFA，研究一下DIj贴个代码

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<queue>
#include<string>
#include<cstring>
#define pa pair<int,int>
using namespace std;

struct node
{
    long long x,y,z,next;
}t[1000010];

long long head[500010];
long long d[5000010];
int n,m,s,x,y,z,tot;

void add(int x,int y,int z)
{
    t[++tot].x = x;
    t[tot].y = y;
    t[tot].z = z;
    t[tot].next = head[x];
    head[x] = tot;
}

void dij(int start)
{
    priority_queue<pa,vector<pa>,greater<pa> >q;
    for(int i = 1;i <= n; ++i) d[i] = 2147483647;
    d[start] = 0;
    q.push(make_pair(0,start));
    while(!q.empty())
    {
        int now = q.top().second;
        q.pop();
        for(int i = head[now];i;i = t[i].next)
        {
            if(d[now] + t[i].z < d[t[i].y])
            {
                d[t[i].y] = d[now] + t[i].z;
                q.push(make_pair(d[t[i].y],t[i].y));
            }
        }
    }
}

int main()
{
    scanf("%d%d%d",&n,&m,&s);
    for(int i = 0;i < m; ++i)
    {
        scanf("%d%d%d",&x,&y,&z);
        add(x,y,z);
    }
    dij(s);
    for(int i = 1;i < n; ++i)
        printf("%lld ",d[i]);
    printf("%lld ",d[n]);
    return 0;
}