Submission #2213856

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Source Code Expand

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

#define int long long

#define rep(i,n) for(int i=0;i<(n);i++)
#define pb push_back
#define all(v) (v).begin(),(v).end()
#define fi first
#define se second
typedef vector<int>vint;
typedef pair<int,int>pint;
typedef vector<pint>vpint;

template<typename A,typename B>inline void chmin(A &a,B b){if(a>b)a=b;}
template<typename A,typename B>inline void chmax(A &a,B b){if(a<b)a=b;}

int N;

set<int>G[111111],H[111111];

signed main(){
    scanf("%lld",&N);
    rep(i,N-1){
        int a,b;
        scanf("%lld%lld",&a,&b);
        a--;b--;
        G[a].insert(b);
        G[b].insert(a);
    }

    queue<pint>que;

    rep(i,N-1){
        int c,d;
        scanf("%lld%lld",&c,&d);
        c--;d--;
        H[c].insert(d);
        H[d].insert(c);

        if(G[c].find(d)!=G[c].end())que.push({c,d});
    }

    rep(i,N-1){
        if(que.size()==0){
            cout<<"NO"<<endl;
            return 0;
        }

        int u,v;
        tie(u,v)=que.front();
        que.pop();
        if(G[u].size()+H[u].size()>G[v].size()+H[v].size())swap(u,v);


        for(auto a:G[u]){
            if(H[v].find(a)!=H[v].end()){
                que.push({v,a});
            }
        }
        for(auto a:H[u]){
            if(G[v].find(a)!=G[v].end()){
                que.push({v,a});
            }
        }

        G[u].erase(v);G[v].erase(u);
        H[u].erase(v);H[v].erase(u);

        for(auto a:G[u]){
            G[a].erase(u);
            G[a].insert(v);
            G[v].insert(a);
        }
        for(auto a:H[u]){
            H[a].erase(u);
            H[a].insert(v);
            H[v].insert(a);
        }
    }
    cout<<"YES"<<endl;
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:23:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld",&N);
                     ^
./Main.cpp:26:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
         scanf("%lld%lld",&a,&b);
                                ^
./Main.cpp:36:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
         scanf("%lld%lld",&c,&d);
                                ^

Judge Result