LeetCode题解之Unique Paths II

1、题目描述

2、问题描述

使用动态规划算法，加上条件检测即可

3、代码

int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
        int m = obstacleGrid.size() ;
        int n = obstacleGrid[0].size() ;
        
        vector<vector<int>> sum(m , vector<int>(n, 0));
        bool isOb = false;
        for( int i = 0; i < m; i++){
            if( obstacleGrid[i][0] == 1) isOb = true;
            if( isOb ){
                sum[i][0] = 0;
            }
            else{
                sum[i][0] = 1;
            }
        }
        
        isOb = false;
        for(int j = 0; j < n; j++){
            if( obstacleGrid[0][j] == 1) isOb = true;
            if( isOb ){
                sum[0][j] = 0;
            }
            else{
                sum[0][j] = 1;
            }
        }
        
        for(int i = 1; i < m; i++){
            for( int j = 1; j < n; j++){
                if( obstacleGrid[i][j] == 1)
                    sum[i][j] == 0;
                else
                    sum[i][j]  = sum[i-1][j] + sum[i][j-1];
            }
        }
        
        return sum[m-1][n-1];
    }