Palindrome Number
程序员文章站
2024-03-22 14:34:28
...
// 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.
/**
* @param {number} x
* @return {boolean}
*/
var isPalindrome = function(x) {
if (x < 0) {
return false;
}
x = x.toString();
return x.reverse() === x;
};
//更优化的算法:模10算法
var isPalindrome2 = function(x) {
if (x < 0 || (x % 10 === 0 && x !== 0)) {
return false;
}
let reverse = 0;
while (x > reverse) {
reverse = reverse * 10 + (x % 10);
x = parseInt(x / 10);
}
return x === reverse || x === parseInt(reverse / 10);
};
isPalindrome2(101);
下一篇: Integer to Roman