Package g0701_0800.s0779_k_th_symbol_in_grammar

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    779 - K-th Symbol in Grammar.

    Medium

    We build a table of n rows ( 1-indexed ). We start by writing 0 in the <code>1<sup>st</sup></code> 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 <code>1<sup>st</sup></code> row is 0, the <code>2<sup>nd</sup></code> row is 01, and the <code>3<sup>rd</sup></code> row is 0110.

    Given two integer n and k, return the <code>k<sup>th</sup></code> ( 1-indexed ) symbol in the <code>n<sup>th</sup></code> row of a table of n rows.

    Example 1:

    Input: n = 1, k = 1

    Output: 0

    Explanation: row 1: <ins>0</ins>

    Example 2:

    Input: n = 2, k = 1

    Output: 0

    Explanation: row 1: 0 row 2: <ins>0</ins>1

    Example 3:

    Input: n = 2, k = 2

    Output: 1

    Explanation: row 1: 0 row 2: 0<ins>1</ins>

    Constraints:

    • 1 &lt;= n &lt;= 30

    • <code>1 <= k <= 2<sup>n - 1</sup></code>

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final Integer kthGrammar(Integer n, Integer k)

      • Methods inherited from class java.lang.Object

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