Submission #3813747

---

Source Code Expand

#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <cstring>
#include <utility>
#include <stack>
using namespace std;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
typedef long long ll;
typedef pair<int,int> pii;
int main(){
    int R,C,n;
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> R>> C >> n;
    vector<bool>on_edge;
    vector<pii>A[4];
    rep(i,n){
        int a,b,c,d;
        cin >> a >> b >> c >> d;
        int cnt = 0;
        if(a==0 or b==0 or a==R or b==C)cnt++;
        if(c==0 or d==0 or c==R or d==C)cnt++;
        if(cnt==2){
            // cerr <<"i = " << i << endl;
            if(a==0)A[0].push_back(pii(b,i));
            else if(b==C)A[1].push_back(pii(a,i));
            else if(a==R)A[2].push_back(pii(b,i));
            else A[3].push_back(pii(a,i));
            swap(a,c);
            swap(b,d);
            if(a==0)A[0].push_back(pii(b,i));
            else if(b==C)A[1].push_back(pii(a,i));
            else if(a==R)A[2].push_back(pii(b,i));
            else A[3].push_back(pii(a,i));
        }
    }
    sort(A[0].begin(),A[0].end());
    sort(A[1].begin(),A[1].end());
    sort(A[2].rbegin(),A[2].rend());
    sort(A[3].rbegin(),A[3].rend());
    vector<int>vec;
    rep(i,4){
        for(auto &x:A[i]){
            vec.push_back(x.second);
            // cerr << x.second << endl;
        }
    }
    stack<int>st;
    for(auto &x:vec){
        if(st.empty()){
            st.push(x);
            continue;
        }
        if(st.top() == x){
            st.pop();
        }else{
            st.push(x);
        }
    }
    if(st.empty()){
        cout << "YES" << endl;
    }else{
        cout << "NO" << endl;
    }
}

Submission Info

Judge Result