给定一个非负整数k(k<=33),返回杨辉三角的第k行
注意:返回行从0开始
在杨辉三角中,每个数是它左上方和右上方的数的和
Example:
Input: 3 Output: [1,3,3,1]
进阶:你可以优化你的算法到O(k)的空间复杂度么?
1:zip()加sum()的方法
def getRow(self, rowIndex):
"""
:type rowIndex: int
:rtype: List[int]
"""
curLevelList = [1]
n = 0
while n<rowIndex:
curLevelList = [sum(t) for t in zip([0]+curLevelList, curLevelList+[0])]
n += 1
return curLevelList
2:map()方法
def getRow(self, rowIndex):
"""
:type rowIndex: int
:rtype: List[int]
"""
curLevelList = [1]
n = 0
while n<rowIndex:
curLevelList = map(lambda x,y:x+y, [0]+curLevelList, curLevelList+[0])
n += 1
return curLevelList
算法题来自:https://leetcode-cn.com/problems/pascals-triangle-ii/description/