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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.
先把两条边初始化了然后dp
class Solution(object): def uniquePathsWithObstacles(self, ob): m, n = len(ob), len(ob[0]) dp = [[0 for i in range(n)] for j in range(m)] for i in range(m): if ob[i][0]: break dp[i][0] = 1 for j in range(n): if ob[0][j]: break dp[0][j] = 1 for i in range(1,m): for j in range(1,n): if ob[i][j]: continue dp[i][j] = dp[i-1][j] + dp[i][j-1] return dp[-1][-1]
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原文地址：http://www.cnblogs.com/lilixu/p/5439915.html
