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.

题意：就有有障碍的机器人路径个数。

思路：多了一个判断障碍的情况，其他的不变。

class Solution {public:    int uniquePathsWithObstacles(vector<vector<int> > &obstacleGrid) {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];    }};