java刷题 动态规划 不同路径||

https://leetcode.cn/problems/unique-paths-ii/submissions/

class Solution {
    public int uniquePathsWithObstacles(int[][] obstacleGrid) {
        //dp数组 dp[i][j] 表示从0 0 到 i j 路径个数
        //递推公式仍为dp[i][j] = dp[i-1][j]+ dp[i][j-1]
        //初始化条件：dp[i][0] = dp[0][j] = 1
        //当第一行或第一列存在障碍时
        //障碍右边或下边 应初始化为0
        int m = obstacleGrid.length, n = obstacleGrid[0].length;
        int[][] dp = new int[m][n];

        //行初始化 i < m && obstacleGrid[i][0] == 0条件不满足 直接跳出for循环
        for(int i = 0; i < m && obstacleGrid[i][0] == 0;i++){
            dp[i][0] = 1;
        }     
        //列初始化
        for(int i = 0; i < n && obstacleGrid[0][i] == 0;i++){
            dp[0][i] = 1;
        }
        //打印dp数组
  //      for(int i =0 ;i < m; i++){
  //          for(int j = 0 ;j < n ;j++){
  //              System.out.print(dp[i][j] + " ");
   //             
    //        }
    //        System.out.print("n");
    //    }
        for(int i = 1; i < m ; i++){
            for(int j = 1; j < n ; j++){
                if(obstacleGrid[i][j] == 1){
                    continue;
                }
                dp[i][j] = dp[i-1][j]+ dp[i][j-1];

            }
        }

        System.out.println(dp[m-1][n-1]);
        return dp[m-1][n-1];
        
   //     return 0;


    }
}