9. Palindrome Number
Determine whether an integer is a palindrome. Do this without extra space.
Some hints:
Could negative integers be palindromes? (ie, -1)
public class Solution { public boolean isPalindrome(int x) { if(x < 0) return false; int ret = reverse(x); if(ret == x) return true; else return false; } public int reverse(int x) { long ret = 0; //long in order to avoid overflow if(x == java.lang.Integer.MIN_VALUE) return 0; //Avoid overflow x = Math.abs(x); while(x != 0){ ret = ret *10 + x%10; x /= 10; } if(ret > java.lang.Integer.MAX_VALUE || ret < java.lang.Integer.MIN_VALUE) return 0; return (int) ret; } }