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) { if(obstacleGrid.empty())return 0; int m=obstacleGrid.size(); int n=obstacleGrid[0].size(); vector<vector<int>> map(m+1); for(int i=0;i<=m;i++)map[i].assign(n+1,0); map[1][0]=1; for(int i=0;i<m;i++){ for(int j=0;j<n;j++){ if(obstacleGrid[i][j])continue; map[i+1][j+1]=map[i][j+1]+map[i+1][j]; } } return map[m][n]; } };