1185-E-Polycrap_and_snakes.Codeforces-mr.convict

/*author* Priyanshu Shrivastav (from IIT Palakkad) *
 * *_ __ ___  _ ______ ___  _ ____   ___  ___| |_  *
 * | '_ ` _ \| '__/ __/ _ \| '_ \ \ / / |/ __| __| *
 * | | | | | | | | (_| (_) | | | \ V /| | (__| |_  *
 * |_| |_| |_|_|(_)___\___/|_| |_|\_/ |_|\___|\__| *
When I wrote this, only God and I understood what I was doing
 ** * * * * * * * Now, only God knows * * * * * * */
#include         <bits/stdc++.h>
using namespace std;
#pragma GCC      optimize ("Ofast")
#pragma GCC      optimize ("unroll-loops")
#pragma GCC      target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#define IOS      ios_base::sync_with_stdio(false); cin.tie (nullptr)
#define PREC     cout.precision (10); cout << fixed
#define bg(x)    " [ " << #x << " : " << (x) << " ]"
#define x        first
#define y        second
using ll = long long;

#define debug(args...) { \
   string _s = #args; replace(_s.begin(), _s.end(), ',', ' ');\
   stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it, args); \
}
void err(istream_iterator<string> it) { it->empty();
   cerr << " (Line : " << __LINE__ << ")" << '\n';
}
template<typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
    cerr << " [ " <<  *it << " : " << a  << " ] "<< ' ';
    err(++it, args...);
}
const int N = 2005;
vector <string> mat;
vector <vector <pair <int, int>>> pos;
int n, m, mx_char;
int mask = 0;
struct solution {
   int xa, ya, xb, yb;
};
solution hash_sol;
bool hash_ok;
vector <solution> sol;

int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};
inline bool is_valid(int xx, int yy) {
   return xx >= 0 && yy >= 0 && xx < n && yy < m;
}

void init() {
   mask = 0;
   mx_char = -1;
   hash_sol = {-1, -1, -1, -1};
   hash_ok = false;
   pos.assign(26, vector <pair <int,int>>());
   sol.clear();
   mat.clear();
}

void read() {
   cin >> n >> m;
   string st;
   for (int i = 0; i < n; ++i) {
      cin >> st;
      mat.push_back(st);
      assert((int)st.size() == m);

      for (int j = 0; j < m; ++j) {
         if (mat[i][j] == '.') continue;
         char ch = mat[i][j];
         mx_char = max(mx_char, int(ch - 'a'));
         pos[int(ch-'a')].push_back(pair <int,int>(i,j));
         mask |= (1 << int(ch - 'a'));
      }
   }
}

void solve(int tc) {
   bool ok = true;

   for (int i = mx_char; i >= 0 && ok; --i) {
      if (mask & (1 << i)) { // present
         //find direction

         int xx = pos[i][0].x, yy = pos[i][0].y;
         int sol_len = 1;

         int this_dir = -1;
         for (int dir = 0; dir < 4; ++dir) {
            int X = xx + dx[dir], Y = yy + dy[dir];
            while (is_valid(X, Y) && (mat[X][Y] == '#' || mat[X][Y] == char(i + 'a'))) {
               if (mat[X][Y] == char(i + 'a')) this_dir = dir;
               X = X + dx[dir], Y = Y + dy[dir];
            }
            if (this_dir != -1) break;
         }
         //change all to '#'

         mat[xx][yy] = '#';
         if (this_dir != -1) {
            int X = xx + dx[this_dir], Y = yy + dy[this_dir];
            while (is_valid(X, Y) && (mat[X][Y] == '#' || mat[X][Y] == char(i + 'a'))) {
               ++sol_len;
               mat[X][Y] = '#';
               X = X + dx[this_dir], Y = Y + dy[this_dir];
            }
         }
         //check if something left
         for (auto le : pos[i]) {
            if (mat[le.x][le.y] != '#') {
               ok = false;
               break;
            }
         }
         //store solution
         if (this_dir == -1) {
            sol.push_back({xx, yy, xx, yy});
            hash_sol = {xx, yy, xx, yy};
         }
         else {
            sol.push_back({xx, yy, xx + dx[this_dir]*(sol_len-1), yy + dy[this_dir]*(sol_len-1)});
            hash_sol = {xx, yy, xx + dx[this_dir]*(sol_len-1), yy + dy[this_dir]*(sol_len-1)};
         }
      }
      else { // not present
         sol.push_back(hash_sol);
      }
   }
   reverse(sol.begin(), sol.end());

   if (ok) {
      cout << "YES\n";
      cout << sol.size() << '\n';
      for (int i = 0; i < (int)sol.size(); ++i) {
         cout << sol[i].xa+1 << ' ' << sol[i].ya+1 << ' ' << sol[i].xb+1 << ' ' << sol[i].yb+1 << '\n';
      }
   }
   else {
      cout << "NO\n";
   }
}

signed main() {
   IOS; PREC;
   int tc;
   cin >> tc;
   for (int i = 1; i <= tc; ++i) {
      init();
      read();
      solve(i);
   }
   return EXIT_SUCCESS;
}