63.Unique Paths II&机器人走方格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) {        vector<vector<int> > f(obstacleGrid.size(), vector<int>(obstacleGrid[0].size()));                    //初始化                 f[0][0] = obstacleGrid[0][0] == 1 ? 0 : 1;          for(int i = 1; i < f.size(); i++)             f[i][0] = obstacleGrid[i][0] == 1 ? 0 : f[i-1][0];                      for(int i = 1; i < f[0].size(); i++)             f[0][i] = obstacleGrid[0][i] == 1 ? 0 : f[0][i-1];                  //填表             for(int i = 1; i < f.size(); i++)             for(int j = 1; j < f[i].size(); j++)                 f[i][j] = obstacleGrid[i][j] == 1 ? 0 : f[i-1][j] + f[i][j-1];                          return f[f.size()-1][f[0].size()-1];                                    }};