LeetCode 09 判断回文数字（难度：Easy）

亦凉 2022-03-02 11:20 232阅读 0赞

**题目大意：判断一个数字是不是回文数字**

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.

这个挺简单，判断一个数字是不是回文数字，前几天在 LeetCode 05 解题过程中也写了一个类似的函数。

package pers.leetcode;
    
    /**
     * LeetCode 09 判断回文数字
     * 难易程度: Easy
     *
     * @author 朱景辉
     * @date 2019/3/20 11:39
     */
    public class PalindromeNumber {
        public static void main(String[] args) {
            int x = 10;
            System.out.println(isPalindrome(x));
        }
    
        /**
         * 判断回文数字
         *
         * @param x int 型数字
         * @return boolean
         */
        public static boolean isPalindrome(int x){
            if (x < 0)
                return false;
            String str = x + "";
            for (int i=0; i<str.length()/2; i++){
                if (str.charAt(i) != str.charAt(str.length()-i-1))
                    return false;
            }
            return true;
        }
    }

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