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Palindrome Integer InterviewBit Solution
Updated: Sep 18, 2020
Problem: Palindrome Integer
Problem Description:
Determine whether an integer is a palindrome. Do this without extra space.
A palindrome integer is an integer x for which reverse(x) = x where reverse(x) is x with its digit reversed. Negative numbers are not palindromic.
Example :
Input : 12121
Output : True Input : 123
Output : FalseApproach
The approach is straight forward, we just convert the given number into a string, and then can check whether the string is palindrome or not.
Another method could be that we can store this number to another number and then reverse one of them.
Time & Space Complexity:
Time Complexity: O(N), N is the number of digits in given numberSpace Complexity: O(1)Solution:
Code in C++
Reading this at https://nouveaucasinos.com, I couldn't help noticing that converting the integer to a string technically uses extra space, which seems to contradict the problem's "without extra space" constraint. In an interview, I'd probably go with reversing just half the number to avoid overflow and stay within O(1) space, even though the negative check is straightforward.