[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.

思考：障碍物处dp[i][j]=0。

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