Determine whether an integer is a palindrome number. Palindrome numbers refer to integers that read in positive order (from left to right) and reverse order (from right to left).
Example 1:
Input: 121
Output: true
Example 2:
Input: -121
Output: false
Explanation: Read from left to right at - 121. Read from right to left, 121-. So it's not a palindrome number.
Example 3:
Input: 10
Output: false
Explanation: Read from right to left, 01. So it's not a palindrome number.
Advance:
Can you solve this problem without converting integers to strings?
package com.ljm.easy.onetofifty;
/**
* Created by linjiaming
*
* Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same
* backward as forward.
*
* Example 1:
*
* Input: 121 Output: true Example 2:
*
* Input: -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: 10 Output: false Explanation: Reads 01 from right to left. Therefore it is not a
* palindrome. Follow up:
*
* Coud you solve it without converting the integer to a string?
*
* Source: LeetCode link: https://leetcode-cn.com/problems/palindrome-number
* Copyright belongs to the seizure network. For commercial reprints, please contact the official authorization. For non-commercial reprints, please indicate the source.
*/
public class PalindromeNumber {
public static void main(String[] args) {
boolean palindrome = isPalindrome(1210121);
System.out.println(palindrome);
}
/**
* @param x
* @return
*/
public static boolean isPalindrome(int x) {
if (x < 0) {
return false;
} else if (x == 0) {
return true;
} else {
if (x % 10 == 0) {
return false;
} else {
int temp = x;
int result = 0;
while (temp != 0) {
int mod = temp % 10;
result = result * 10 + mod;
temp = temp / 10;
}
if (result == x) {
return true;
} else {
return false;
}
}
}
}
}