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

Example 1:

Input: 123
Output: 321
Example 2:

Example 2:

Input: -123
Output: -321
Example 3:

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: [−2^31, 2^31 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

給定一個32位有符號整型數，將它反轉輸出。注意可以儲存的32位有符號整型數範圍是[-2^31,2^31-1]。

注意反轉後的數可能超出範圍。所以該數需要用比int範圍大的型別來儲存。

class Solution {
public:
    int reverse(int x) {
        long res = 0;
        while(x!=0)
        {
            res = res * 10 + x % 10;
            x /= 10;
        }
        if (res > INT_MAX || res < INT_MIN) 
        {
            return
 
 0;
        }
        return res;       
    }
};

Runtime: 30 ms