func_code_string: #include <bits/stdc++.h>   #pragma comment(linker,  /STACK:256000000 )   using namespace std;   vector<char> cc;   void solve() {     int n, m, k, d = 0;     cin >> n >> m >> k;     vector<string> arr(n), ans(n);     for (int i = 0; i < n; i++) {       cin >> arr[i];       ans[i].resize(m);       for (int j = 0; j < m; j++) d += (arr[i][j] ==  R );     }     vector<int> cnt;     for (int i = 0; i < k - d % k; i++) cnt.push_back(d / k);     for (int i = 0; i < d % k; i++) cnt.push_back(d / k + 1);     vector<int> have(k);     int ptr = 0;     for (int i = 0; i < n; i++) {       if (i % 2 == 0) {         for (int j = 0; j < m; j++) {           char cur = cc[ptr];           ans[i][j] = cur;           have[ptr] += (arr[i][j] ==  R );           if (have[ptr] == cnt[ptr] && ptr < k - 1) ptr++;         }       } else {         for (int j = m - 1; j >= 0; j--) {           char cur = cc[ptr];           ans[i][j] = cur;           have[ptr] += (arr[i][j] ==  R );           if (have[ptr] == cnt[ptr] && ptr < k - 1) ptr++;         }       }     }     for (int i = 0; i < n; i++) cout << ans[i] <<   n ;   }   int main() {     srand(1373737);     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     for (char c =  0 ; c <=  9 ; c++) cc.push_back(c);     for (char c =  a ; c <=  z ; c++) cc.push_back(c);     for (char c =  A ; c <=  Z ; c++) cc.push_back(c);     int t;     cin >> t;     while (t--) solve();     return 0;   }   