- Pascal's Triangle II Easy
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Share 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.
In Pascal's triangle, each number is the sum of the two numbers directly above it.
Example:
Input: 3 Output: [1,3,3,1] Follow up:
Could you optimize your algorithm to use only O(k) extra space?
思路：新建一数组，存放[1,1,1,1,1...] 遍历nums，从后往前填充数据
代码：python3
class Solution:
def getRow(self, rowIndex: int) -> List[int]:
row=[1]+[0]*(rowIndex)
for i in range(1,rowIndex+1):
for j in range(i,0,-1):
row[j]=row[j-1]+row[j]
return row
时间复杂度：O(m^2) 空间复杂度：O(m)
