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.

class Solution {
public:
int uniquePathsWithObstacles(vector<vector<int> > &obstacleGrid)
{
int m=obstacleGrid.size();
if(m==0) return 0;

int n=obstacleGrid[0].size();
int path
;
path[0]=1-obstacleGrid[0][0];
for(int i=1;i<n;i++)
if(obstacleGrid[0][i]==1) path[i]=0;
else path[i]=path[i-1];

for(int i=1;i<m;i++)
{
if(obstacleGrid[i][0]==1) path[0]=0;
for(int j=1;j<n;j++)
if(obstacleGrid[i][j]==1) path[j]=0;
else path[j]=path[j-1]+path[j];
}
return path[n-1];
}
};