1192-counting-rooms.cpp

#include <bits/stdc++.h>
using namespace std;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);

#define ll long long
#define vi vector<int>
#define vl vector<long long>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define umap unordered_map
#define uset unordered_set

#define rall(x) (x).rbegin(), (x).rend()
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define mp make_pair

const long long LLINF = LLONG_MAX;
const int INF = INT_MAX;
const int MOD = 1e9 + 7;

void solve() {
    int n, m;
    cin >> n >> m;

    vector<string> grid(n);
    for (int i = 0; i < n; i++) {
        cin >> grid[i];
    }

    vector<vector<bool>> visited(n, vector<bool>(m, false));
    int rooms = 0;

    vi dx = {-1, 1, 0, 0};
    vi dy = {0, 0, -1, 1};

    function<void(int, int)> dfs = [&](int x, int y) {
        visited[x][y] = true;
        for (int dir = 0; dir < 4; dir++) {
            int nx = x + dx[dir];
            int ny = y + dy[dir];
            if (nx >= 0 && nx < n && ny >= 0 && ny < m && grid[nx][ny] == '.' && !visited[nx][ny]) {
                dfs(nx, ny);
            }
        }
    };

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (grid[i][j] == '.' && !visited[i][j]) {
                dfs(i, j);
                rooms++;
            }
        }
    }

    cout << rooms << "\n";
}

int main() {
    fastio

    int tc = 1; // Number of test cases
    // cin >> tc;

    while (tc--) {
        solve();
    }

    return 0;
}