func_code_string: #include <bits/stdc++.h>   using namespace std;   int k, t;   char n1[10005];   char n2[10005];   int swapindex[2];   bool same(char x[], char y[], int n) {     for (int i = 0; i < n; i++) {       if (x[i] != y[i]) {         return false;       }     }     return true;   }   int ham(char x[], char y[], int n) {     int temp = 0;     for (int i = 0; i < n; i++) {       if (x[i] != y[i]) {         temp++;       }     }     return temp;   }   int main() {     cin >> k;     for (int i = 0; i < k; i++) {       cin >> t;       for (int l = 0; l < t; l++) {         cin >> n1[l];       }       for (int l = 0; l < t; l++) {         cin >> n2[l];       }       if (ham(n1, n2, t) == 2) {         int temp = 0;         for (int i = 0; i < t; i++) {           if (n1[i] != n2[i]) {             swapindex[temp] = i;             temp++;           }         }         swap(n1[swapindex[0]], n2[swapindex[1]]);         if (same(n1, n2, t)) {           cout <<  Yes  << endl;         } else {           cout <<  No  << endl;         }       } else {         cout <<  No  << endl;       }     }     return 0;   }   