63. Unique Paths II

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

.

Note: m and n will be at most 100.

解答：

class Solution {
public:
int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
int row=obstacleGrid.size();
int col=obstacleGrid[0].size();
vector<vector<int>>d(row+1,vector<int>(col+1,0));
d[0][1]=1;
for(int i=1;i<=row;i++){
for(int j=1;j<=col;j++){
if(!obstacleGrid[i-1][j-1])
d[i][j]=d[i][j-1]+d[i-1][j];
}
}
return d[row][col];
}
};