9_PalindromeNumber - a920604a/leetcode GitHub Wiki
- Bit Manipulation
- Math
categories: leetcode
comments: false
title: 9. Palindrome Number
tags:problem
solution
class Solution {
public:
bool isPalindrome(int x) {
// 0, 1,2,3,4,5,6,7,8,9 => true
// 10 , 100, x0, x00 => false
if (x < 0 || (x % 10 == 0 && x != 0)) return false;
int ret = 0;
while(ret < x){
ret = 10*ret + (x%10);
x/=10;
}
return ( ret==x || ret/10 == x);
}
};
analysis
- time complexity
O(logn)
- space complexity
O(1)