每天(?)一道Leetcode(12) Pascal's Tri

Array

119. Pascal's Triangle II

Given a non-negative index where , return the index row of the Pascal's triangle.
Note that the row index starts from .

即输出杨辉三角中的第k行
杨辉三角的每一行组合数其实可以通过计算得到
比如第三行是 对应
所以只要知道计算方法就ok，
[yeah~~~这是我自己做的第二个beats ]

class Solution:
    def getRow(self, rowIndex):
        """
        :type rowIndex: int
        :rtype: List[int]
        """
        res = []
        k = rowIndex
        nums = jc(k)
        for i in range(k+1):
            res.append(int(nums/(jc(i)*jc(k-i))))
        return res
    
    
    
    
def jc(n):
    if n==0:
        return 1
    else:
        s = 1
        for i in range(1,n+1):
            s = s*i
        return s