15Jan2023.java

int water_flow(int [][] mat, int N, int M) {
		//Write your code here
		boolean indian[][]=new boolean[N][M];
        boolean arabian[][]=new boolean[N][M];
    
        for(int i=0;i<N;i++) dfs(mat, indian, i, 0, N, M);
        for(int i=0;i<M;i++) dfs(mat, indian, 0, i, N, M);
        for(int i=0;i<N;i++) dfs(mat, arabian, i, M-1, N, M);
        for(int i=0;i<M;i++) dfs(mat, arabian, N-1, i, N, M);
    
        int count = 0;
        for(int i=0;i<N;i++){
            for(int j=0;j<M;j++){
                if(indian[i][j] && arabian[i][j]){
                    count++;
                }        
            }
        }
    
        return count;
	}
	void dfs(int mat[][], boolean vis[][], int i, int j, int n, int m){

        if(i<0 || j<0 || i>=n || j>=m || vis[i][j]) return;
        vis[i][j] = true;
    
        if(i>0 && !vis[i-1][j] && mat[i-1][j] >= mat[i][j]){
            dfs(mat, vis, i-1, j, n, m);
        }
        if(i<n-1 && !vis[i+1][j] && mat[i+1][j] >= mat[i][j]){
            dfs(mat, vis, i+1, j, n, m);
        } 
        if(j>0 && !vis[i][j-1] && mat[i][j-1] >= mat[i][j]){
            dfs(mat, vis, i, j-1, n, m);
        } 
        if(j<m-1 && !vis[i][j+1] && mat[i][j+1] >= mat[i][j]){
            dfs(mat, vis, i, j+1, n, m);
        } 
    }