119. Pascal's Triangle II (python)

Given an index k, return the kth row of the Pascal’s triangle.
For example, given k = 3,
Return [1,3,3,1].
Note:
Could you optimize your algorithm to use only O(k) extra space?
题意：返回杨辉三角的k行
思路：和118. Pascal’s Triangle，只是此处行数从0开始，k=3对应第四行
Runtime: 55 ms

class Solution(object):    def getRow(self, rowIndex):        tem=[0,1]        for i in range(rowIndex+1):            rowlist=[]            for j in range(len(tem)-1):                rowlist.append(tem[j]+tem[j+1])            tem=rowlist[:]            tem.insert(0,0)            tem.append(0)        return  rowlist