Description
https://oj.leetcode.com/problems/palindrome-number/
Difficulty: 2.5/5.0
Analysis and solution
The main thing you want to avoid in this problem is overflow. If you reverse the integer, it overflows for 1111119999. If you write while(x/(10 * unitHigh)), it overflows for any integer greater or equal to 1 billion.
class Solution {
public:
bool isPalindrome(int x) {
if (x < 0)
return false;
int unitHigh = 1;
while(x/10/unitHigh)
unitHigh *= 10;
while(x){
if (x/unitHigh != x %10)
return false;
x = (x % unitHigh)/10;
unitHigh /=100;
}
return true;
}
};