LeetCode.7.Reverse Integer

原题链接：Reverse Integer

题目内容： 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 hold integers within the 32-bit signed integer range. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

翻转整数，注意int类型范围

C++

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

Python

class Solution(object):
    def reverse(self, x):
        """
        :type x: int
        :rtype: int
        """
        x = int(str(x)[::-1]) if x >= 0 else - int(str(-x)[::-1])
        return x if x < 2147483647 and x >= -2147483648 else 0

Leetcode的sys.maxint数值为9223372036854775807，所以还是直接使用32位的数字范围。