LeetCode-7(Reverse Integer)

Reverse digits of an integer.

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

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Note:
The input is assumed to be a 32-bit signed integer. Your function should return 0 when the reversed integer overflows.

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class Solution {public:    int reverse(int x) {        int y = x %100;        if(x >=  2147483648 || x < -2147483648 || x==0)  return 0;  //溢出        else if(x/1000000000>0 && (y>=22 || y<=-22))  return 0;  //溢出        int sign = 0;        if(x>=0) sign = 1;        else sign = -1;        x=x*sign;        int ans = 0;        while(x > 0){            ans = ans*10 + x%10;            x = x/10;        }        if(ans >=  2147483648 || ans < 0)  return 0;  //溢出        else return ans*sign;    }};