745B - Hongcow Solves A Puzzle - CodeForces Solution

// Online C++ compiler to run C++ program online
#include <bits/stdc++.h>
using namespace std;

int main() {
    int n,m; cin>>n>>m; char arr[n][m];
    for(int i=0;i<n;i++) for(int j=0;j<m;j++) cin>>arr[i][j];
    vector<vector<int>>v; vector<int>v1,ch;
    
    for(int i=0;i<n;i++){ for(int j=0;j<m;j++) { 
   if(arr[i][j]=='X') {v1.push_back(j); }  }
   if(v1.size()>0){ v.push_back(v1); v1.clear();ch.push_back(i);}
      }
    
    
    for(int i=1;i<v.size();i++){
        if(v[i].size()!=v[0].size()) {  cout<<"NO"; return 0;}      }
 //       cout<<v.size()<<" "<<v[0].size()<<endl;
    for(int i=1;i<v.size();i++){  
        for(int j=0;j<v[0].size();j++){
            if(v[0][j]!=v[i][j]){  cout<<"NO"; return 0;} } }
            
 for(int i=1;i<ch.size();i++){ if(ch[i]!=ch[i-1]+1) { cout<<"NO"; return 0;} }            
            
            cout<<"YES";
    

    return 0;
}