func_code_string: #include <bits/stdc++.h>   #pragma GCC optimize( O3 )   #pragma GCC target( tune=native )   #pragma GCC optimize( fast-math )   using namespace std;   const int DEBUG = 0;   mt19937 gen(       (unsigned)chrono::high_resolution_clock::now().time_since_epoch().count());   #pragma comment(linker,  /STACK:16777216 )   void solve() {     int h, w;     cin >> h >> w;     vector<string> a(h);     vector<int> x1(26, 1000000000), x2(26, -1), y1(26, 1000000000), y2(26, -1);     for (int i = 0; i < h; i++) {       cin >> a[i];       for (int j = 0; j < w; j++) {         if (a[i][j] ==  . ) continue;         int k = (a[i][j] -  a );         x1[k] = min(x1[k], j);         x2[k] = max(x2[k], j);         y1[k] = min(y1[k], i);         y2[k] = max(y2[k], i);       }     }     int ok = 1;     int last = -1;     int last_ch = -1;     for (int i = 0; i < 26; i++) {       if (x1[i] != 1000000000) last_ch = i;     }     for (int i = 0; i < 26; i++) {       if (x1[i] == 1000000000) {         if (i <= last_ch && last_ch != -1) {           x1[i] = x1[last_ch];           x2[i] = x2[last_ch];           y1[i] = y1[last_ch];           y2[i] = y2[last_ch];         }         continue;       }       last = i;       if (x1[i] != x2[i] && y1[i] == y2[i])         ;       else if (x1[i] == x2[i] && y1[i] != y2[i])         ;       else if (x1[i] == x2[i] && y1[i] == y2[i])         ;       else         ok = 0;     }     if (!ok) {       cout <<  NO n ;       return;     }     vector<string> b(h, string(w,  . ));     int cnt = 0;     for (int k = 0; k < 26; k++) {       if (x1[k] == 1000000000) continue;       ++cnt;       for (int i = y1[k]; i <= y2[k]; i++)         for (int j = x1[k]; j <= x2[k]; j++) b[i][j] = char( a  + k);     }     for (int i = 0; i < h; i++)       for (int j = 0; j < w; j++)         if (a[i][j] != b[i][j]) ok = 0;     if (!ok) {       cout <<  NO n ;       return;     }     cout <<  YES n ;     cout << cnt <<   n ;     for (int i = 0; i < cnt; i++) {       cout << y1[i] + 1 <<     << x1[i] + 1 <<     << y2[i] + 1 <<                << x2[i] + 1 <<   n ;     }   }   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.setf(cout.fixed);     cout.precision(12);     auto START_TIME = chrono::high_resolution_clock::now();     int test;     cin >> test;     while (test--) {       solve();     }     return 0;   }   