Leetcode63. Different paths II

Title transmission address ：https://leetcode.cn/problems/unique-paths-ii/

Operational efficiency ：

The code is as follows ：

 public static int uniquePathsWithObstacles(int[][] obstacleGrid) {
    
        int m = obstacleGrid.length-1;
        int n = obstacleGrid[0].length-1;
        return uniquePaths(m, n, obstacleGrid);

    }

    public static int uniquePaths(int m, int n, int[][] obstacleGrid) {
    
        HashMap<String, Integer> map = new HashMap<>();
        return uniqPathsWithMap(m, n, obstacleGrid, map);
    }

    public static int uniqPathsWithMap(int m, int n, int[][] obstacleGrid, HashMap<String, Integer> map) {
    
        if (obstacleGrid[m][n] == 1) {
    
            return 0;
        }
        String key = m + ":" + n;
        if (map.containsKey(key)) {
    
            return map.get(key);
        }
        // Dealing with border situations 
        if (m == 0) {
    
            while (n>0){
    
                if(obstacleGrid[0][n-1]==1){
    
                    return 0;
                }
                n--;
            }
            return 1;
        }
        if(n==0){
    
            while (m>0){
    
                if(obstacleGrid[m-1][0]==1){
    
                    return 0;
                }
                m--;
            }
            return 1;
        }
        // If you want to walk to (m,n) coordinates , Yes 2 Maybe , The first is from (m-1,n) To (m,n),  The first 2 One is from (m,n-1) To (m,n)
        int i = uniqPathsWithMap(m - 1, n, obstacleGrid, map) + uniqPathsWithMap(m, n - 1, obstacleGrid, map);
        map.put(m + ":" + n, i);
        return i;
    }