Given a 32-bit signed integer, reverse digits of an integer.
Example 1:Input: 123Output: 321Example 2:Input: -123Output: -321Example 3:Input: 120Output: 21
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.
This is a Leetcode easy level interview problem. The best and easiest way to approach this problem is through the use of strings.
Here is a step by step approach of the solution:
Step 1: Create a variable and convert the integer into a string by storing the absolute value. Strip all the leading zeros and then reverse the string. Afterwards store the output as an integer.
def reverse_integer(n): y = str(abs(n)) y = y.strip() y = y[::-1] output = int(y)
Step 2: Check if the output is in the range or not. If it is overflown return zero.
if output >= 2** 31 -1 or output <= -2** 31: return 0 elif n < 0: return -1 * outputelse: return output
And that is a simple detailed approach of how to solve this problem. The full code for this problem is shown below as well.
def reverse_integer(n): y = str(abs(n)) y = y.strip() y = y[::-1] output = int(y) if output >= 2** 31 -1 or output <= -2** 31: return 0 elif n < 0: return -1 * output else: return output
The time complexity in this solution is O(n).
This problem is common with companies like Google therefore it’s important to have a grasp of the solution. See you on the next interview problem! Happy coding!