Description
Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-231, 231 - 1], then return 0.
Assume the environment does not allow you to store 64-bit integers (signed or unsigned).
Example 1:
Input: x = 123 Output: 321
Example 2:
Input: x = -123 Output: -321
Example 3:
Input: x = 120 Output: 21
Constraints:
-231 <= x <= 231 - 1
Code
class Solution {
public:
int reverse(int x) {
int rev = 0;
while(x) {
int digit = x % 10;
x /= 10;
// check overflow
if ((rev > 0 && rev > (INT_MAX - digit)/10) | (rev < 0 && rev < (INT_MIN - digit)/10)) return 0;
rev = rev * 10 + digit;
}
return rev;
}
};