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.

这道题和62题没啥区别，只要将路障处设为0就可以了

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