1. class Solution {
    2. public:
    3.     int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
    4.         int m = obstacleGrid.size();
    5.         int n = obstacleGrid[0].size();
    6.         vector<vector<int> > dp(m+1, vector<int>(n+1, 0));
    7.         dp[0][0] = obstacleGrid[0][0] == 0? 1: 0;
    8.         for(int i = 1; i< m; i++){
    9.             dp[i][0] = dp[i-1][0]>0 && obstacleGrid[i][0] == 0? 1: 0;
    10.         }
    12.         for(int j = 1; j< n; j++){
    13.             dp[0][j] = dp[0][j-1]>0 &&obstacleGrid[0][j] == 0? 1: 0;
    14.         }
    15.         for(int i = 1; i<m; i++){
    16.             for(int j = 1; j<n; j++){
    17.                 if(obstacleGrid[i][j] == 1){
    18.                     dp[i][j]= 0;
    19.                 }else{
    20.                     dp[i][j] = dp[i][j-1] + dp[i-1][j];
    21.                 }
    23.             }
    24.         }
    26.         return dp[m-1][n-1];
    28.     }
    29. };