func_code_string: #include <bits/stdc++.h>   using namespace std;   long long gcd(long long a, long long b) {     if (b == 0) return a;     return gcd(b, a % b);   }   long long lcm(long long a, long long b) { return (a * b) / gcd(a, b); }   int main() {     long long t, i, r, c, k, j, n, cnt, x, y, p, q, l, flag;     vector<string> a;     vector<char> b;     for (i = 48; i < 58; i++) {       b.push_back(char(i));     }     for (i = 65; i < 91; i++) {       b.push_back(char(i));     }     for (i = 97; i < 124; i++) {       b.push_back(char(i));     }     string s;     cin >> t;     for (i = 0; i < t; i++) {       cin >> r >> c >> n;       cnt = 0;       p = 0, q = 0, l = 0, flag = 1;       for (j = 0; j < r; j++) {         cin >> s;         for (k = 0; k < c; k++) {           if (s[k] ==  R ) {             cnt++;           }         }         a.push_back(s);       }       if (cnt % n == 0) {         x = cnt / n;         y = n;       } else {         x = cnt / n + 1;         y = cnt % n;       }       for (j = 0; j < r; j++) {         if (j % 2 == 0) {           for (k = 0; k < c; k++) {             if (a[j][k] ==  R ) {               if (q == x) {                 p++;                 if (p == y && flag == 1) {                   x = x - 1;                   flag = 2;                 }                 q = 1;                 l++;                 a[j][k] = b[l];               } else {                 q++;                 a[j][k] = b[l];               }             } else {               a[j][k] = b[l];             }           }         } else {           for (k = c - 1; k >= 0; k--) {             if (a[j][k] ==  R ) {               if (q == x) {                 p++;                 if (p == y && flag == 1) {                   x = x - 1;                   flag = 2;                 }                 q = 1;                 l++;                 a[j][k] = b[l];               } else {                 q++;                 a[j][k] = b[l];               }             } else {               a[j][k] = b[l];             }           }         }       }       for (j = 0; j < r; j++) {         cout << a[j] << endl;       }       a.clear();     }   }   