[LeetCode]题解(python):119 Pascal's Triangle II
题目来源
https://leetcode.com/problems/pascals-triangle-ii/
Given an index k, return the kth row of the Pascal's triangle.
For example, given k = 3,
Return [1,3,3,1]
.
题意分析
Input:integer
Output:kth row of the Pascal's triangle
Conditions:只返回第n行
题目思路
同118,不同之处在于只返回某一层,同时注意与上题的下标起点不一样(rowIndex先加个1 = =)
AC代码(Python)
1 class Solution(object): 2 def getRow(self, rowIndex): 3 """ 4 :type rowIndex: int 5 :rtype: List[int] 6 """ 7 rowIndex += 1 8 ans = [] 9 if rowIndex == 0: 10 return [] 11 for i in range(rowIndex): 12 this = [] 13 for j in range(i+1): 14 this.append(1) 15 if i > 1: 16 for x in range(i - 1): 17 this[x+1] = ans[i-1][x] + ans[i-1][x+1] 18 print this 19 ans.append(this) 20 21 return ans[rowIndex - 1]