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.采用动态规划解决*/class Solution {public:    int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {        int m=obstacleGrid.size(),n=obstacleGrid[0].size();vector<int> dp(m+1,0);dp[1]=1;for(int i=0;i<n;i++)for(int j=1;j<=m;j++)if(obstacleGrid[j-1][i]) dp[j]=0;    else dp[j]+=dp[j-1];return dp[m];    }};