Help me in solving CONVERT problem

help
,
1

My issue

What am I missing here?

My code

#include <bits/stdc++.h>

using namespace std;

int main() {
    int tcase;
    long n, k;
    string s, t;
    cin >> tcase;
    while (tcase--) {
        cin >> n >> k;
        cin >> s >> t;
        long match_count = 0, unmatch_count = 0, one_s = 0, one_t = 0;
        for (long i = 0; i < n; i++) {
            if (s[i] == '1') one_s++;
            if (t[i] == '1') one_t++;
            if (s[i] == t[i]) match_count++;
            else unmatch_count++;
        }
        unmatch_count /= 2;
        if (one_t != one_s) cout << "NO" << endl;
        else if (unmatch_count > k) cout << "NO" << endl;
        else if ((n == 2) && (unmatch_count % 2 == 0) && k % 2 == 0) cout << "YES" << endl;
        else if ((n == 2) && (unmatch_count % 2 == 1) && k % 2 == 1) cout << "YES" << endl;
        else if ((n == 2) && (unmatch_count % 2 + k % 2) % 2 == 1) cout << "NO" << endl;
        else if (unmatch_count <= k) cout << "YES" << endl;
        else if (s == t) cout << "NO" << endl;
        else cout << "YES" << endl;
    }

}

Problem Link: Binary Conversion Practice Coding Problem

2

@amanraj_7
for test case
3 2
0 1 1
0 1 1
the answer would be yes but your code will print no.