leetcode[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.

class Solution {

public:

int uniquePathsWithObstacles(vector<vector<int> > &obstacleGrid) 

{

    int m=obstacleGrid.size();

    int n=obstacleGrid[0].size();

    vector<int> ivec(n);

    vector<vector<int>> f(m, ivec);

    f[0][0]=obstacleGrid[0][0]==1?0:1;

    for (int ki=1;ki<m;ki++)

    {

        f[ki][0]=obstacleGrid[ki][0]==1?0:f[ki-1][0];

    }

    for (int kj=1;kj<n;kj++)

    {

        f[0][kj]=obstacleGrid[0][kj]==1?0:f[0][kj-1];

    }

    for (int i=1;i<m;i++)

    {

        for (int j=1;j<n;j++)

        {

            f[i][j]=obstacleGrid[i][j]==1?0:f[i-1][j]+f[i][j-1];

        }

    }

    return f[m-1][n-1];

}

};