<LeetCode>03_09_Palindrome Number

문제

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.

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.

Example 4:

Input: x = -101
Output: false

작성코드

public class Solution {
    public bool IsPalindrome(int x) {

        if (x < 0)
        {
            return false;
        }

        int leng = 0;
        int o = x;
        Stack<int> stack = new Stack<int>();

        while(x > 0)
        {
            stack.Push(x%10);
            x /= 10;
            leng++;
        }

        for (int i = 0; i < leng/2; i++)
        {
            if (o%10 != stack.Pop())
            {
                return false;
            }

            o /= 10;
        }

        return true;
    }
}

배운점

• reverseNumber = reverseNumber * 10 + (x % 10); 정수역순은 해당 방식을 사용하자.