7. Reverse Integer

7. Reverse Integer

Question:

Given a 32-bit signed integer, reverse digits of an integer.

Example 1:

Input: 123
Output: 321

Example 2:

Input: -123
Output: -321

Example 3:

Input: 120
Output: 21

Note: Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−231, 231 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

Thinking:

class Solution {
	public int reverse(int x) {
			boolean nagative = (x < 0);
			long temp = (long)Math.abs(x);
			long res= 0;
			while(temp != 0){
					res *= 10;
					res += (temp % 10);
					temp /= 10;
			}
			res = nagative ? res * -1 : res;
			return (int)((res > Integer.MAX_VALUE || res < Integer.MIN_VALUE) ? 0: res);
	}
}