LeetCode_Reverse Integer_ Day 0x3

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Reverse Integer

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

Submissions:

class Solution {
    public int reverse(int x) {
        int result = 0;
        while (x != 0)
        {
            int low = x % 10;
            result = result * 10 + low;
            x = x / 10;
        }

        return result;
    }
}

Solution:

class Solution {
    public int reverse(int x) {
        int result = 0;
        while (x != 0)
        {
            int low = x % 10;
            int newResult = result * 10 + low;
            if ((newResult - low) / 10 != result)
            { return 0; }
            result = newResult;
            x = x / 10;
        }

        return result;
    }
}

 Summary:

         第一次提交忽略了可能反转后会溢出的情况，-2147483648~2147483647。