counting_rooms.cpp

// #include<bits/stdc++.h>
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <algorithm>
#include <cstring>
#include <cstdlib>
#include <numeric>
#include <cmath>

using namespace std;

typedef long long ll;
typedef long double ld;

#define FOR(i, a, b) for(int i=a; i<(b); i++)

void readArray(int arr[], int n);
void dfs(int v, vector<int> &components,  bool visited[], vector<int> graph[]);

const char nl = '\n';

void solution(){
    //write your code here
    int n, m;
    cin >> n >> m;
    char matrix[n][m];
    FOR(i, 0, n){
        FOR(j, 0, m){
            char ch;
            cin >> ch;
            matrix[i][j]=ch;
        }
    }
    vector<int> graph[n*m];
    int count=0;
    FOR(i, 0, n){
        FOR(j, 0, m){
            bool right=true, left=true, up=true, down=true;
            if(matrix[i][j]=='.'){
                if(i+1<n && matrix[i+1][j]=='.'){
                    graph[(i*m)+j].push_back(((i+1)*m)+j);
                    down=false;
                }
                if(i-1>=0 && matrix[i-1][j]=='.'){
                    graph[(i*m)+j].push_back(((i-1)*m)+j);
                    up=false;
                }
                if(j+1<m && matrix[i][j+1]=='.'){
                    graph[(i*m)+j].push_back(((i)*m)+j+1);
                    right=false;
                }
                if(j-1>=0 && matrix[i][j-1]=='.'){
                    graph[(i*m)+j].push_back(((i)*m)+j-1);
                    left=false;
                }
                if(right && left && up && down){
                    count+=1;
                }
            }
        }
    }
    bool visited[n*m];
    memset(visited, false, sizeof(visited));
    vector<int> components;
    FOR(i, 0, n*m){
        if(!visited[i]){
            components.clear();
            dfs(i, components, visited, graph);
            if(components.size()>1){
                count+=1;
            }
        }
    }
    cout << count << nl;
}

int main() {
    //fast i/o
    ios_base::sync_with_stdio(false);cin.tie(NULL);

    int T=1;
    // cin >> T;
    while(T--){
        solution();
    }
    return 0;
}

/*
ASCII OF NUMBERS 0-9             ==> [48, 57]
ASCII OF UPPERCASE ALPHABETS A-Z ==> [65, 90]
ASCII OF LOWERCASE ALPHABETS a-z ==> [97, 122]
ASCII OF WHITESPACE              ==> [32]
ASCII OF SPECIAL CHARACTERS I    ==> [33, 47]
ASCII OF SPECIAL CHARACTERS II   ==> [58, 64]
ASCII OF SPECIAL CHARACTERS III  ==> [91, 96]
ASCII OF SPECIAL CHARACTERS IV   ==> [123, 126]

SPECIAL CHARATERS I ==> [!,",#,$,%,&,',(,),*,+...,/]
*/

void readArray(int arr[], int n){
    for(int i=0; i<n; ++i){
        cin >> arr[i];
    }
}
void dfs(int v, vector<int> &components,  bool visited[], vector<int> graph[]){
    visited[v]=true;
    components.push_back(v);
    FOR(i, 0, graph[v].size()){
        if(!visited[graph[v][i]]){
            dfs(graph[v][i], components, visited, graph);
        }
    }
}