dijkstra

洛谷模板题链接：https://www.luogu.org/problem/P3371

#include <iostream>
#include <vector>
#include <cstring>
#include <cstdio>
using namespace std;
const int N   = 1e5 + 10;
const int INF = 2147483647;

//n = 顶点数; m = 边数; s = 起点 
int n, m, s;

//第一个数是距离，第二个数为顶点 
vector<pair<int,int> > g[N];
int dist[N];
bool vis[N];

void dijkstra(int s)
{
    memset(vis, 0, sizeof(vis));
    for(int i = 1; i <= n; i++)    dist[i] = INF;
    dist[s] = 0;
    while(1)
    {    
        int node = -1;
        int minDist = INF;
        
        //在为标记的点中找到距离起点的最短距离 
        for(int i = 1; i <= n; i++)
        {
            if(vis[i] == 0 && dist[i] < minDist)
            {
                node = i;
                minDist = dist[i];
            }
        }
        
        if(node == -1)    break;
        //标记该点 
        vis[node] = 1;
        
        //更新 
        for(int i = 0; i < g[node].size(); i++)
        {
            int v = g[node][i].second;
            dist[v] = min(dist[v], dist[node] + g[node][i].first);
        }
            
    }
}

int main()
{
    cin >> n >> m >> s; 
    for(int i = 1; i <= m; i++)
    {
        int u, v, d;
        scanf("%d %d %d", &u, &v, &d);
        g[u].push_back(make_pair(d, v)); 
    }
    dijkstra(s);
    for(int i = 1; i <= n; i++)    
        i==1?cout<<dist[i]:cout<<" "<<dist[i];
    return 0;
}

这是没有加优化的，数据加强的话，就会TLE。