7.reverse-integer.cpp

/*
 * [7] Reverse Integer
 *
 * https://leetcode.com/problems/reverse-integer/description/
 *
 * algorithms
 * Easy (24.40%)
 * Total Accepted:    409.8K
 * Total Submissions: 1.7M
 * Testcase Example:  '123'
 *
 * 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.
 * 
 */
class Solution {
public:
    int reverse(int x) {
	long long int ans = 0;
	while (x) {
		int t = x%10;
		ans = ans*10+t;
		x = x/10;
	}
	return ans > INT_MAX || ans < INT_MIN ? 0 : ans;        
    }
};