【leetcode】 Unique Path ||(easy)

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.

思路：跟Unique Paths差不多，就是把有障碍的地方方法数变成0，注意左上角为障碍的情况

class Solution {
public:
    int uniquePathsWithObstacles(vector<vector<int> > &obstacleGrid) {
        if(obstacleGrid.empty())
        {
            return ;
        }
        vector<vector<int>> ways(obstacleGrid.size(), vector<int>(obstacleGrid[].size(),));
        if(obstacleGrid[][] == )
        {
            ways[][] = ;
        }
        for(int c = ; c < obstacleGrid[].size(); c++)
        {
            ways[][c] = (obstacleGrid[][c] == ) ?  : ways[][c - ];
        }
        for(int r = ; r < obstacleGrid.size(); r++)
        {
            ways[r][] = (obstacleGrid[r][] == ) ?  : ways[r - ][];
        }
        for(int i = ; i < obstacleGrid.size(); i++)
        {
            for(int j = ; j < obstacleGrid[].size(); j++)
            {
                ways[i][j] = (obstacleGrid[i][j] == ) ?  : ways[i - ][j] + ways[i][j - ];
            }
        }
        return ways[obstacleGrid.size() - ][obstacleGrid[].size() - ];
    }
};