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.

Java

http://blog.csdn.net/linhuanmars/article/details/22126357

public class Solution {
    public int uniquePathsWithObstacles(int[][] obstacleGrid) {
        if(obstacleGrid.length < 1 && obstacleGrid[0].length < 1) {
            return 0;
        }

        int row = obstacleGrid.length;
        int col = obstacleGrid[0].length;
        int[][] rst = new int[row][col];
        rst[0][0] = obstacleGrid[0][0] == 1 ? 0 : 1;
        for(int i = 1; i < col; i++) {
            rst[0][i] = (obstacleGrid[0][i] == 1 || rst[0][i - 1] == 0) ? 0 : 1;
        }
        for(int i = 1; i < row; i++) {
            rst[i][0] = (obstacleGrid[i][0] == 1 || rst[i - 1][0] == 0) ? 0 : 1;
        }

        for(int i = 1; i < row; i++) {
            for(int j = 1; j < col; j ++) {
                if(obstacleGrid[i][j] == 1) {
                    rst[i][j] = 0;
                } else {
                    rst[i][j] = rst[i - 1][j] + rst[i][j - 1];
                }
            }
        }
        return rst[row - 1][col - 1];
    }
}