[LeetCode] 7. Reverse Integer

7. Reverse Integer

 

Given a 32-bit signed integer, reverse digits of an integer.

 

Example 1:

Input: 123 Output: 321

Example 2:

Input: -123 Output: -321

Example 3:

Input: 120 Output: 21

 

Note:
Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−231,  231 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

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코드

#include <iostream>
using namespace std;

class Solution {
public:
	int reverse(int x) {
        long long int answer = 0;

        while (x != 0) {
        	// INT_MAX가 overflow, underflow가 일어나는 조건에 맞춰 0을 반환한다.
            if (((answer * 10) > INT_MAX) || ((answer * 10) < INT_MIN))
                return 0;
            answer *= 10;
            answer += x % 10;
            x /= 10;
        }
        return answer;
    }
};


int main() {
	int n;
	cout << "-2,147,483,646 ~ 2,147,483,647 사이의 값을 입력하세요 :";
	cin >> n;
	Solution s;
	cout << s.reverse(n);

	return 0;
}

Success

Runtime: 0 ms, faster than 100.00% of C++ online submissions for Reverse Integer.

Memory Usage: 5.9 MB, less than 100.00% of C++ online submissions for Reverse Integer.