DSA/C++/LeetCode/0200.cpp at main · spycedcoffee/DSA · GitHub

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class Solution {
public:
    void dfs(vector<vector<char>>& grid, int i, int j){

        if(i < 0 || i >= grid.size() || j < 0 || j >= grid[0].size())
            return;

        if(grid[i][j] == '0' || grid[i][j] == '2')
            return;

        grid[i][j] = '2';

        dfs(grid, i + 1, j);
        dfs(grid, i - 1, j);
        dfs(grid, i, j + 1);
        dfs(grid, i, j - 1);
    }

    int numIslands(vector<vector<char>>& grid) {

        int cnt = 0;

        for(int i = 0; i < grid.size(); i++){

            for(int j = 0; j < grid[0].size(); j++){

                if(grid[i][j] == '1'){
                    dfs(grid, i, j);
                    cnt++;
                }
            }
        }

        return cnt;
    }
};