Leetcode 63. Unique Paths II

question:

Follow up for "Unique Paths":

Now consider if some obstacles are added to the grids. How many unique paths would there be?

An obstacle and empty space is marked as 

1

 and 

0

 respectively
in the grid.

For example,

There is one obstacle in the middle of a 3x3 grid as illustrated below.

[
[0,0,0],
[0,1,0],
[0,0,0]
]

The total number of unique paths is 

2

.

Analysis:
The same with the first question: otherwise, there is obstacles

ublic class Solution {
public int uniquePaths(int[][] obstacleGrid) {
int m = obstacleGrid.length;
int n = obstacleGrid[0].length;
int[][]dp = new int[m]
;
for(int i = 0; i < m; i++){
if(obstacleGrid[i][0] == 1)
dp[i][0] = 0;
else{
dp[i][0] = 1;
}
}
for(int i = 0; i < n; i++){
if(obstacleGrid[i][0] == 1)
dp[0][i] = 0;
else{
dp[0][i] = 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];
}
}