Spfa 模板

#include <cstdio>
#include <cmath>
#include <cstring>
#include <queue>
#include <algorithm>
#define INF 0x3F3F3F3F
using namespace std;

const int MAXN = (int)(1e4 + 10);
const int MAXM = (int)(1e5 + 10);

int n, ml, md, dist[MAXN];
int size, head[MAXN], point[MAXM], val[MAXM], nxt[MAXM];

void add (int from, int to, int value)
{
    val[size] = value;
    point[size] = to;
    nxt[size] = head[from];
    head[from] = size++;
}

bool  spfa(int s)
{
    int cnt[MAXN];
    bool vis[MAXN];
    queue<int> q;
    memset(vis, false, sizeof vis);
    memset(dist, 0x3f, sizeof dist);
    memset(time, 0, sizeof time);
    
    q.push(s);
    vis[s] = true;
    dist[s] = 0;
    while(!q.empty()){
        int u = q.front();
        q.pop();
        vis[u] = false;
        for(int i = head[u]; ~i; i = nxt[i]){
            if(dist[point[i]] > dist[u] + val[i]){
                dist[point[i]] = dist[u] + val[i];
                if(!vis[point[i]]){
                    vis[point[i]] = true;
                    q.push(point[i]);
                    if(++cnt[point[i]] > n) return false;
                }
            }
        }
    }
    return true;
}