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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 0respectively 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.
public class Solution { /** * @param obstacleGrid: A list of lists of integers * @return: An integer */ public int uniquePathsWithObstacles(int[][] obstacleGrid) { // write your code here if(obstacleGrid == null || obstacleGrid.length == 0 || obstacleGrid[0] == null || obstacleGrid[0].length == 0) return 0; if(obstacleGrid[0][0] == 1) return 0; int m = obstacleGrid.length; int n = obstacleGrid[0].length; int[][] result = new int[m][n]; for(int i = 0; i < m; i++){ if(obstacleGrid[i][0] == 1){ while(i < m){ result[i][0] = 0; i++; } } else result[i][0] = 1; } for(int i = 0; i < n; i++){ if(obstacleGrid[0][i] == 1){ while(i < n){ result[0][i] = 0; i++; } } else result[0][i] = 1; } for(int i = 1; i < m; i++){ for(int j = 1; j < n; j++){ if(obstacleGrid[i][j] == 0) result[i][j] = result[i - 1][j] + result[i][j - 1]; else result[i][j] = 0; } } return result[m - 1][n - 1]; } }
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原文地址：http://www.cnblogs.com/goblinengineer/p/5260439.html
