9. Palindrome Number

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临睡前做一题吧

Description

Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.

Example

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?

Solution

没什么难度直接放代码吧

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/**
 * @param {number} x
 * @return {boolean}
 */
var isPalindrome = function(x) {
    let arr = (x+"").split('');
    let i=0,j=arr.length-1;
    if (arr.length===1)return true;
    if (arr.length===2)return arr[0] === arr[j];
    while (i<j){
        if (arr[i]!==arr[j]){
            return false;
        }
        i++;
        j--;
    }

    return true;
};

有个follow up是不要转成字符串，可以把逐位数拿出来放到数组就一样的了。