Given a non-negative index k where k ≤ 33, return the kth index row of the Pascal‘s triangle.
Note that the row index starts from 0.
只额外开O（k）的空间，那就开一个两行k列的数组，滚动记录上一次的结果就行
class Solution(object): def getRow(self, rowIndex): """ :type rowIndex: int :rtype: List[int] """ ans = [[1] * (rowIndex + 1), [1] * (rowIndex + 1)] for index in range(1, rowIndex + 2, 1): for i in range(1, index - 1, 1): ans[index % 2][i] = ans[(index - 1) % 2][i] + ans[(index - 1) % 2][i - 1] return ans[(rowIndex + 1) % 2]
原文：https://www.cnblogs.com/whatyouthink/p/13260505.html