func_code_string: #include <bits/stdc++.h>   using namespace std;   void hike() {     int64_t n;     cin >> n;     string s, t;     cin >> s >> t;     vector<int64_t> f;     for (int64_t i = 0; i < n; ++i) {       if (s[i] != t[i]) {         f.push_back(i);       }     }     if (f.size() != 2) {       cout <<  No n ;       return;     }     char x1 = s[f[0]], y1 = t[f[0]];     char x2 = s[f[1]], y2 = t[f[1]];     s[f[0]] = y2;     t[f[1]] = x1;     if (s == t) {       cout <<  Yes n ;       return;     }     s[f[0]] = x1;     t[f[1]] = y2;     s[f[1]] = y1;     t[f[0]] = x2;     if (s == t) {       cout <<  Yes n ;       return;     }     cout <<  No n ;   }   signed main() {     ios_base::sync_with_stdio(false);     cin.tie(nullptr);     cout.tie(nullptr);     int64_t t = 1;     cin >> t;     while (t--) hike();     return 0;   }   