[LeetCode] 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.

同上题，稍作修改。

class Solution {
public:
    int uniquePathsWithObstacles(vector<vector<int> > &obstacleGrid) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<vector<int> > f(obstacleGrid.size(), vector<int>(obstacleGrid[0].size()));
               
        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];
            
        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];
    }
};