leetcode[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.
class Solution { public: int uniquePathsWithObstacles(vector<vector<int> > &obstacleGrid) { int m=obstacleGrid.size(); int n=obstacleGrid[0].size(); vector<int> ivec(n); vector<vector<int>> f(m, ivec); f[0][0]=obstacleGrid[0][0]==1?0:1; for (int ki=1;ki<m;ki++) { f[ki][0]=obstacleGrid[ki][0]==1?0:f[ki-1][0]; } for (int kj=1;kj<n;kj++) { f[0][kj]=obstacleGrid[0][kj]==1?0:f[0][kj-1]; } for (int i=1;i<m;i++) { for (int j=1;j<n;j++) { f[i][j]=obstacleGrid[i][j]==1?0:f[i-1][j]+f[i][j-1]; } } return f[m-1][n-1]; } };