题目

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?

解题

取一半整数进行对比

  public static boolean isPalindrome(int x) {
    if (x < 0 || (x % 10 == 0 && x != 0)) {
      return false;
    }

    int converx = 0;
    while (x > converx) {
      int mod = x % 10;
      converx = converx * 10 + mod;
      x = x / 10;
    }
    return converx == x || converx / 10 == x;
  }

参考资料：
https://leetcode.com/problems/palindrome-number/solution/