63. 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.
题目大意：在中间加了个障碍物，考虑的情况多了，但是还是动态规划

class Solution {public:    int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {        int F[100][100];        int rows = obstacleGrid.size(), cols = obstacleGrid[0].size();        if(obstacleGrid[0][0] == 1)            F[0][0] = 0;        else             F[0][0] = 1;        for(int j = 1; j < cols; ++j){            if(obstacleGrid[0][j] == 1)                F[0][j] = 0;            else                 F[0][j] = F[0][j - 1];        }        for(int i = 1; i < rows; ++i){            if(obstacleGrid[i][0] == 1)                F[i][0] = 0;            else                 F[i][0] = F[i - 1][0];            for(int j = 1; j < cols; ++j){                if(obstacleGrid[i][j] == 1)                    F[i][j] = 0;                else {                    F[i][j] = F[i][j - 1] + F[i - 1][j];                }            }        }        return F[rows - 1][cols - 1];    }};