NoOfPathObstruction.java

public class NoOfPathObstruction {

    public int count(int [][] arrA, int row, int col){
        //base case
        //check if last cell is reached since after that only one path
        if(row==arrA.length-1 && col==arrA.length-1){
            return 1;
        }
        int right =0;
        int down = 0;
        if(row!=arrA.length-1 && arrA[row+1][col]!=-1){
            right = count(arrA, row+1, col);
        }
        if(col!=arrA.length-1 && arrA[row][col+1]!=-1){
            down = count(arrA, row, col+1);
        }
        return right + down;
    }

    public int countDP(int [][] arrA){
        int result [][] = arrA;

        for (int i = 1; i <result.length ; i++) {
            for (int j = 1; j <result.length ; j++) {
                if(result[i][j]!=-1){
                    result[i][j]=0;
                    if(result[i-1][j]>0)
                        result[i][j]+=result[i-1][j];
                    if(result[i][j-1]>0)
                        result[i][j]+=result[i][j-1];
                }
            }
        }

        return result[arrA.length-1][arrA.length-1];
    }

    public static void main(String[] args) {
        int arrA [][] = {{1,1,1},{1,-1,1},{1,-1,1}};
        NoOfPathObstruction noOfPaths = new NoOfPathObstruction();
        System.out.println("No Of Path (Recursion):- " +noOfPaths.count(arrA,0,0));
        System.out.println("No Of Path (DP):- " +noOfPaths.countDP(arrA));
    }
}