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) { vector<vector<int> > grid(obstacleGrid.size(),vector<int>(obstacleGrid[0].size())); grid[0][0] = obstacleGrid[0][0] == 1 ? 0 : 1; for(int i=1;i<grid.size();i++) grid[i][0]=obstacleGrid[i][0] == 1 ? 0 : grid[i-1][0]; for(int j=1;j<grid[0].size();j++) grid[0][j]=obstacleGrid[0][j]== 1 ? 0 : grid[0][j-1]; for(int i=1;i<grid.size();i++) for(int j=1;j<grid[i].size();j++) grid[i][j]=obstacleGrid[i][j]==1 ? 0 : grid[i][j-1]+grid[i-1][j]; return grid[grid.size()-1][grid[0].size()-1]; } };
原文：http://www.cnblogs.com/li303491/p/4078877.html