LeetCode | Reverse Integer

Reverse digits of an integer.

Example1: x = 123, return 321

Example2: x = -123, return -321

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Have you thought about this?

Here are some good questions to ask before coding. Bonus points for you if you have already thought through this!

If the integer’s last digit is 0, what should the output be? ie, cases such as 10, 100.

Did you notice that the reversed integer might overflow? Assume the input is a 32-bit integer, then the reverse of 1000000003 overflows. How should you handle such cases?

For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

反转一个int数字，需要注意的是INT_MAX和INT_MIN的处理

class Solution {
public:
int reverse(int x) {
int temp= x;
//我知道了，INT_MIN绝对值比INT_MAX大1
//所以不可以一上来就将x取绝对值
// printf("x %d sign %d temp %d\n",x,sign,temp);
int sum=0;
while(temp){
//判断越界
if((INT_MAX/10 < sum) || (INT_MAX/10==sum && ((INT_MAX%10) < (temp%10))))
return 0;
if((INT_MIN/10 > sum) || (INT_MIN/10 ==sum && ((INT_MIN%10 )>(temp%10) )) )
return 0;
sum=sum*10+temp%10;
temp/=10;
}
return sum;
}
};