How to resolve the algorithm Find palindromic numbers in both binary and ternary bases step by step in the Ruby programming language

Published on 12 May 2024 09:40 PM

How to resolve the algorithm Find palindromic numbers in both binary and ternary bases step by step in the Ruby programming language

Table of Contents

Problem Statement

It's permissible to assume the first two numbers and simply list them.

Let's start with the solution:

Step by Step solution about How to resolve the algorithm Find palindromic numbers in both binary and ternary bases step by step in the Ruby programming language

The code you provided defines a Ruby enumerator named pal23 that generates palindromic numbers in base 3 and base 2. Palindromic numbers are numbers that read the same backwards and forwards, such as 121 or 1001.

The enumerator is defined using the Enumerator.new method, which takes a block that defines the elements of the enumerator. In this case, the block contains a loop that generates palindromic numbers and yields them to the enumerator.

The loop begins by yielding the numbers 0 and 1. Then, it uses a for loop to iterate over the range from 1 to Float::INFINITY. For each number i in this range, the loop performs the following steps:

  1. Converts i to a string representation in base 3 using the to_s(3) method.
  2. Creates a new number n by concatenating the base-3 representation of i with the digit "1" and the reverse of the base-3 representation of i.
  3. Converts n to a base-2 string representation using the to_s(2) method.
  4. Checks if the length of the base-2 string representation of n is odd and if the string is a palindrome (i.e., it reads the same backwards and forwards).
  5. If the conditions in step 4 are met, the loop yields the number n to the enumerator.

The code then uses the times method to iterate 6 times, and for each iteration it calls the next method on the pal23 enumerator to retrieve the next palindromic number. The number is then printed to the console along with its base-3 and base-2 string representations.

Here is an example of the output of the code:

        decimal          ternary                          binary
0:          0 0                             0
1:          1 1                             1
2:         10 21                             101
3:         121 10101                           11111
4:         202 110110                          1010101
5:         222 12121                           1101101

Source code in the ruby programming language

pal23 = Enumerator.new do |y|
  y << 0
  y << 1
  for i in 1 .. 1.0/0.0                 # 1.step do |i|  (Ruby 2.1+)
    n3 = i.to_s(3)
    n = (n3 + "1" + n3.reverse).to_i(3)
    n2 = n.to_s(2)
    y << n  if n2.size.odd? and n2 == n2.reverse
  end
end

puts "         decimal          ternary                          binary"
6.times do |i|
  n = pal23.next
  puts "%2d: %12d %s %s" % [i, n, n.to_s(3).center(25), n.to_s(2).center(39)]
end


  

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