最短路-SPFA

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
void SPFA(int s) {
    for(int i = 0; i <= n; i++) {
        dis[i] = (1 << 30);
    }
    dis[s] = 0;
    vis[x] = 1;
    q[1] = s;
    int head = 0, tail = 1;
    while(head < tail) {
        head++;
        v = Q[head];
        vis[v] = 0;
        for(int i = 0; i <= n; i++) {
            if(a[v][i] > 0 && dis[i] > dis[v] + a[v][i]) {
                dis[i] = dis[v] + a[v][i];
                if(!vis[i]) {
                    tail++;
                    q[tail] = i;
                    vis[i] = 1;
                }
            }
        }
    }
}
int main() {

    return 0;
}