# Unique Paths II

Total Accepted: 31019 Total Submissions: 110866

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.

## SOULUTION 1:

LeetCode: Unique Paths 解题报告 相比，只不过是判断一下当前是不是block，如果是block,直接设置D[i][j] 是0就好了 也就是不可达。 同样在3分钟之内Bug free 秒答，哦耶！  1 public class Solution {
2     public int uniquePathsWithObstacles(int[][] obstacleGrid) {
3         // 1150
4         if (obstacleGrid == null || obstacleGrid.length == 0 || obstacleGrid.length == 0) {
5             return 0;
6         }
7
8         int rows = obstacleGrid.length;
9         int cols = obstacleGrid.length;
10
11         int[][] D = new int[rows][cols];
12
13         for (int i = 0; i < rows; i++) {
14             for (int j = 0; j < cols; j++) {
15                 D[i][j] = 0;
16                 if (obstacleGrid[i][j] == 1) {
17                     D[i][j] = 0;
18                 } else {
19                     if (i == 0 && j == 0) {
20                         D[i][j] = 1;
21                     }
22
23                     if (i != 0) {
24                         D[i][j] += D[i - 1][j];
25                     }
26
27                     if (j != 0) {
28                         D[i][j] += D[i][j - 1];
29                     }
30                 }
31             }
32         }
33
34         return D[rows - 1][cols - 1];
35     }
36 }
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posted on 2015-04-08 03:04  Yu's Garden  阅读(560)  评论(0编辑  收藏