[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];

    }

};