[アルゴリズム]LeetCode-Palindrome番号

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easy leetcode algorithm テキストリンク

LeetCode - Palindrome Number


問題の説明

Given an integer x, return true if x is palindrome integer.

An integer is a palindrome when it reads the same backward as forward. For example, 121 is palindrome while 123 is not.using integer division.

I/O例


Example 1:
Input: x = 121
Output: true
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.

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Constraints:

-231 <= x <= 231 - 1

Solution

class Solution {
    public boolean isPalindrome(int x) {

        if (x < 0) {
            return false;
        }

        int reverseNumber = 0;
        int originNumber = x;
        while (x > 0) {
            int rest = x % 10;
            x = x / 10;

            reverseNumber = reverseNumber * 10 + rest;
        }

        if (originNumber == reverseNumber) {
            return true;
        }
        return false;

    }
}
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