Reverse Integer

Reverse digits of an integer.

Example1: x = 123, return 321
Example2: x = -123, return -321

要求反转后的数溢出时返回0，比如1000000003

public int reverse(int x) {int sum = 0;while (x != 0) {if (sum * 10.0 > Integer.MAX_VALUE || sum * 10.0 < Integer.MIN_VALUE) {return 0;}sum *= 10;sum += sum + x % 10.0 > Integer.MAX_VALUE ? 0 : x % 10;x /= 10;}return sum;    }

上溢和下溢都要判断，注意判断条件 sum * 10.0 等不要写成 sum * 10