Reverse digits of an integer.
Example1: x = 123, return 321
Example2: x = -123, return -321
Note:
The input is assumed to be a 32-bit signed integer. Your function should return 0 when the reversed integer overflows.
将一个整数中的数字进行颠倒，当颠倒后的整数溢出时，返回 0 (标记为 32 位整数)。

分析

通过取余得到最后一位，循环，对于溢出进行判断即可

代码

public int reverse(int x) {
        int result = 0;

        while(x != 0) {
            int tail = x % 10;
            int newResult = result * 10 + tail;
            if((newResult-tail)/10 != result)
                return 0;
            result = newResult;
            x = x/10;
        }
        return result;
    }

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