代码如下

#include <bits/stdc++.h>
const int maxn = 15005;
using namespace std;
int n, m;
int dis[maxn];
int cnt[maxn];
bool vis[maxn];
int x, y, v, pd;
queue<int>st;
vector<pair<int , int >>in[maxn];
int read();
bool spfa(int s) {
    vis[s] = true;
    dis[s] = 0;
    st.push(s);
    while (!st.empty()) {
        for(int i=1;i<=n;i++){dis[i]=0x7fffffff;}
        int now = st.front();
        vis[now] = false;
        st.pop();
        for (pair<int , int > v : in[now]) {
            if (dis[v.first] > dis[now] + v.second) {
                dis[v.first] = dis[now] + v.second;
                if (!vis[v.first]) {
                    st.push(v.first);
                    vis[v.first] = true;
                    cnt[v.first]++;
                    if (cnt[v.first] >= n-1)return false;
                }
            }
        }
    }
    return true;
}
int main() {
    //freopen("in.txt","r",stdin);
    //freopen("out.txt","w",stdout);

    n = read(); m = read();
    for (int i = 1; i <= n; i++) {in[0].push_back({i, 0});}
    for (int i = 1; i <= m; i++) {
        pd = read();
        x = read(), y = read();
        if (pd == 1) {
            v = read();
            in[x].push_back({y, -v});
        } else if (pd == 2) {
            in[y].push_back({x, v});

        } else if (pd == 3) {
            in[y].push_back({x, 0}); 
            in[x].push_back({y, 0}); 
        }

    }
    if (spfa(0)) {puts("Yes");return 0;};
    cout<<"No"<<'\n';
    return 0;
}


int read() {
    int x = 0, w = 1; char ch = 0;
    while (ch < '0' || ch > '9') {  if (ch == '-') w = -1; ch = getchar();}
    while (ch >= '0' && ch <= '9') { x = x * 10 + (ch - '0'); ch = getchar();}
    return x * w;
}

就35分QwQ