7. Reverse Integer

题目：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.

class Solution {
public:
    int reverse(int x) {
    }
};

我的代码如下，该题比较简单，注意定义result的类型是long long类型

class Solution {
public:
    int reverse(int x) {
        long long flag=1,result=0;
        if(x<0)
           {flag=-1;x=abs(x);} 
        while(x)
        {
            result=result*10+ x%10;
            x=x/10;
        }
        return(flag*result<INT_MIN || flag*result>INT_MAX) ? 0 : flag*result;
    }
};

其实本题也不用考虑x是否是正负值；代码简化如下：

class Solution {
public:
    int reverse(int x) {
        long long res = 0;
        while(x) {
            res = res*10 + x%10;
            x /= 10;
        }
        return (res<INT_MIN || res>INT_MAX) ? 0 : res;
    }
};