UniquePathsII63.java

public class Solution {
    public int uniquePathsWithObstacles(int[][] obstacleGrid) {
        
        int m=obstacleGrid.length;
        int n=obstacleGrid[0].length;
        int dp[][] = new int[m][n];
        
        if(obstacleGrid[0][0]==1){
            dp[0][0] = 0;
            return 0;
        }
        else{
            dp[0][0] = 1;
        }
        
        for(int i=1;i<n;i++){
            if(obstacleGrid[0][i]==1 || dp[0][i-1]==0){
                dp[0][i] = 0;
            }
            else{
                dp[0][i] = 1;;
            }
        }
        
        for(int i=1;i<m;i++){
            if(obstacleGrid[i][0]==1 || dp[i-1][0]==0){
                dp[i][0] = 0;
            }
            else{
                dp[i][0] = 1;;
            }
        }
        
        for(int i=1;i<m;i++){
            for(int j=1;j<n;j++){
              if(obstacleGrid[i][j]==1){
                  dp[i][j] = 0;
              }
              else{
                  dp[i][j] = dp[i-1][j]+dp[i][j-1];
              }
            }
        }
        
        return dp[m-1][n-1];
    }
}