9. Palindrome Number

Easy

Problem Description

9. Palindrome Number

Easy


Given an integer x, return true if x is a palindrome, and false otherwise.

 

Example 1:

Input: x = 121
Output: true
Explanation: 121 reads as 121 from left to right and from right to left.

Example 2:

Input: x = -121
Output: false
Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.

Example 3:

Input: x = 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.

 

Constraints:

  • -231 <= x <= 231 - 1

 

Follow up: Could you solve it without converting the integer to a string?

Solution

0009-palindrome-number.java

java
0009-palindrome-number.java
1class Solution { 2 public boolean isPalindrome(int x) { 3 //reversing digits 4 if(x<0||(x%10==0 && x!=0)) return false; 5 int reversedHalf=0; 6 while(x>reversedHalf){ 7 reversedHalf=x%10+10*reversedHalf; 8 x/=10; 9 } 10 return reversedHalf==x||x==reversedHalf/10; 11 } 12}
LeetCode Practice