Unique PatUnique Paths II

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