题目
We build a table of n rows (1-indexed). We start by writing 0 in the 1st row. Now in every subsequent row, we look at the previous row and replace each occurrence of 0 with 01, and each occurrence of 1 with 10.
For example, for n = 3, the 1st row is 0, the 2nd row is 01, and the 3rd row is 0110. Given two integer n and k, return the kth (1-indexed) symbol in the nth row of a table of n rows.
解题思路
k = k - 1
f(n,k) = f(n-1,k/2) if n % 2 == 0
1 - f(n-1, k/2) else
代码
class Solution:
def kthGrammar(self, n: int, k: int) -> int:
def f(n, k):
if n == 1:
return 0
return f(n - 1, k // 2) if k % 2 == 0 else 1 - f(n - 1, k // 2)
k -= 1
return f(n, k)
