1848A - Vika and Her Friends

Hello CF! Could you explain to me why these two codes output different results?

Problem 1848A: Vika and Her Friends

My Code:

#include <iostream>
#include <vector>
using namespace std;
typedef long long ll;

void solve() {
    ll n, m, k; //Size of mall and # of Vika's friends
    ll x, y; //Vika's coordinate
    cin >> n >> m >> k >> x >> y;

    //For each of vika's friends, check whether they are in the same square as her. If so, print NO
    for(int i = 0; i < k; i++) {
        int xx, yy;
        cin >> xx;
        cin >> yy;
//!!! PROBLEM SEEMS TO BE HERE vvv!!!
        if((x + y) % 2 == (xx + yy) % 2) { 
            cout << "NO" << endl;
            return;
        }
    }
    cout << "YES" << endl;
//!!! PROBLEM SEEMS TO BE HERE ^^^!!!
}

int main() {
    int t;
    cin >> t;
    while(t--) {
        solve();
    }
}

Editorial's code:

#include <bits/stdc++.h>
 
using namespace std;
 
#define int long long
 
int32_t main() {
    int t;
    cin >> t;
    while (t--) {
        int n, m, k;
        cin >> n >> m >> k;
        int x, y;
        cin >> x >> y;
        string ans = "YES\n";
        for (int i = 0; i < k; ++i) {
            int xx, yy;
            cin >> xx >> yy;
            if ((x + y) % 2 == (xx + yy) % 2) {
                ans = "NO\n";
            }
        }
        cout << ans;
    }
    return 0;
}

The problem seems to be inside the for-loop. I used a different method to output a "NO" when it's found that one of Vika's friend is on the same square colour as Vika. This method seems to yield an incorrect result when there's a previous test case ('t') that outputs a 'NO' already (although I could be wrong).

I asked ChatGPT several times with different prompts on why these two code output different results, but I'm still quite confused. Out of options, I have to resort to asking you guys. Would be really nice if you guys could help a little newbie like me. Thanks!