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DSA · Math · #132

Palindrome Number

Module 58 · difficulty 2/5·⏱ 30:00starts on first keystroke

Given an integer `x`, return `true` if `x` is a palindrome, and `false` otherwise. An integer is a palindrome when it reads the same forward and backward. For example, `121` is a palindrome while `123` is not. Implement the function `isPalindrome(x)`. **Follow up:** Could you solve it without converting the integer to a string?

Examples
  • x = 121 → true — Reads as 121 from left to right and from right to left.
  • x = -121 → false — From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.
  • x = 10 → false — Reads 01 from right to left. Therefore it is not a palindrome.
Constraints
  • · -2^31 <= x <= 2^31 - 1
Session phases
A · Clarify
B · Approach
C · Complexity
D · Edges
E · Code
F · Tradeoff
G · Score
Phase A — Clarify
Ask questions about input bounds, types, and edge constraints.
Ask the coach clarifying questions about the problem.
When you've covered this phase, advance to the next.