Maths: Reverse a number

Reverse a number

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 [-2<sup>31</sup>, 2<sup>31</sup> - 1], then return 0.

class Solution {
    public int reverse(int x) {
        boolean checkSignFlag = false;
        if(x<0) {
            checkSignFlag = true;
            x = -x;
        }

        long reverse = 0;
        while(x>0) {
            int digit = x%10;
            reverse = reverse * 10 + digit;
            x = x/10;
        }

          if(reverse > Integer.MAX_VALUE || reverse<Integer.MIN_VALUE){
            return 0;
        }

        if ( checkSignFlag ) {
            return (int)(-1 * reverse);
        } else {
            return (int)reverse;
        }
    }
}

Input

x = 1534236469

Output

1056389759

Expected

0

Time complexity

O(log n)

Space complexity

O(1)

Time taken