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Check Palindrome Number

Certification: Basic Level Accuracy: 0% Submissions: 0 Points: 5

Write a JavaScript program to determine if a given integer is a palindrome number. A palindrome number reads the same backward as forward. You should solve this without converting the integer to a string.

Example 1
    
      
  • Input: num = 121
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  • Output: true
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  • Explanation: 
    • The number 121 reads the same from left to right and right to left. 
    • When we reverse 121, we get 121. 
    • Since the original number equals its reverse, it is a palindrome. 
    • Therefore, the output is true.
    •
Example 2
    
      
  • Input: num = -121
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  • Output: false
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  • Explanation: 
    • The number -121 has a negative sign at the beginning. 
    • When reversed, it would be 121- which is not a valid number format. 
    • Negative numbers cannot be palindromes due to the negative sign. 
    • Therefore, the output is false.
    •
Constraints
    
      
  • -2^31 ≤ num ≤ 2^31 - 1
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  • You cannot convert the integer to a string
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  • Negative numbers should return false
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  • Time Complexity: O(log n) where n is the input number
    • 
      
  • Space Complexity: O(1)
    •
NumberControl StructuresHCL TechnologiesPhillips
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Hint
Solution

Solution Hints

    
      
  • Handle negative numbers first - they cannot be palindromes
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  • Use mathematical operations to reverse the number digit by digit
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  • Extract the last digit using the modulo operator (num % 10)
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  • Remove the last digit by integer division (Math.floor(num / 10))
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  • Build the reversed number by multiplying the current reversed number by 10 and adding the extracted digit
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  • Continue this process until the original number becomes 0
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  • Compare the original number with the reversed number to determine if it's a palindrome
    •

Steps to solve by this approach:

 Step 1: Check if the number is negative, if so return false immediately
 Step 2: Store the original number in a variable for later comparison
 Step 3: Initialize a variable to store the reversed number, starting with 0
 Step 4: Use a while loop to continue until the number becomes 0
 Step 5: Extract the last digit using modulo operation (num % 10)
 Step 6: Build the reversed number by multiplying current reversed by 10 and adding the extracted digit
 Step 7: Remove the last digit from the original number using integer division
 Step 8: Compare the original number with the reversed number and return the result

Submitted Code :