[LeetCode] Reverse Integer

Problems:

Reverse digits of an integer.

Example1: x = 123, return 321
Example2: x = -123, return -321

Solution: O(n) 

public class Solution {
    public static int reverse(int x) {
        int index = 1;
        int value = x;
        if(x<0){
            index = -1;
            value = -x;
        }
        int ret = 0;
        while(value >0){
            int v = value%10;
            ret = ret*10 + v;
            value/=10;
        }
        return ret*index;
    }
}     

Key concept: we should always consider last digit is 0 and will overflow after revert but the solution only concern revertable