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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 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.
1 public class Solution { 2 public int uniquePathsWithObstacles(int[][] obstacleGrid) { 3 if (obstacleGrid == null || obstacleGrid.length == 0 || obstacleGrid[0].length== 0) { 4 return 0; 5 } 6 7 int n = obstacleGrid.length; 8 int m = obstacleGrid[0].length; 9 int[][] paths = new int[n][m]; 10 11 for (int i = 0; i < n; i++) { 12 if (obstacleGrid[i][0] != 1) { 13 paths[i][0] = 1; 14 } else { 15 break; 16 } 17 } 18 19 for (int i = 0; i < m; i++) { 20 if (obstacleGrid[0][i] != 1) { 21 paths[0][i] = 1; 22 } else { 23 break; 24 } 25 } 26 27 for (int i = 1; i < n; i++) { 28 for (int j = 1; j < m; j++) { 29 if (obstacleGrid[i][j] != 1) { 30 paths[i][j] = paths[i - 1][j] + paths[i][j - 1]; 31 } else { 32 paths[i][j] = 0; 33 } 34 } 35 } 36 return paths[n - 1][m - 1]; 37 } 38 }
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原文地址：http://www.cnblogs.com/FLAGyuri/p/5324924.html
