Submission #3813879

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
ll const inf = 1e18;

vector<vector<pair<int,int>>> vec;

ll dfs(int v1, int v2, int p, ll c){
    if(v1 == v2){
        return c;
    }
    auto itr = vec.at(v1).begin();
    while(itr != vec.at(v1).end()){
        if((*itr).first == p){
            itr++;
            continue;
        }
        ll d = dfs((*itr).first, v2, v1, c + (*itr).second);
        if(d != inf){
            return d;
        }
        itr++;
    }
    return inf;
}

int main(void){
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n, m;
    cin >> n >> m;
    string ans = "Yes";
    
    vec.resize(n);
    for(int i=0; i<m; i++){
        int a, b, c;
        cin >> a >> b >> c;
        vec.at(a-1).push_back({b-1,c});
        vec.at(b-1).push_back({a-1,-c});
        ll d = dfs(a-1, b-1, -1, 0);
        if(d != inf && d != c){
            ans = "No";
        }
    }

    cout << ans << endl;

    return 0;
}

Submission Info

Judge Result