g0701_0800.s0779_k_th_symbol_in_grammar

Class Solution

java.lang.Object

g0701_0800.s0779_k_th_symbol_in_grammar.Solution

public class Solution
extends Object

779 - K-th Symbol in Grammar.

Medium

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.

Example 1:

Input: n = 1, k = 1

Output: 0

Explanation: row 1: 0

Example 2:

Input: n = 2, k = 1

Output: 0

Explanation: row 1: 0 row 2: 01

Example 3:

Input: n = 2, k = 2

Output: 1

Explanation: row 1: 0 row 2: 01

Constraints:

• 1 <= n <= 30
• 1 <= k <= 2n - 1

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	kthGrammar(int n, int k)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

kthGrammar

public int kthGrammar(int n,
                      int k)