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Reverse Integer - Leetcode #7 Short & Simple Solution

Updated: Jun 1, 2022

In our previous article we solved the two sum problem.This is another article in the series leetcode problem solutions and this article is a solution to leetcode 7 two sum problem.


Given a 32-bit signed integer x, reverse the digits in x and return the result. If after reversing, the result goes outside the signed 32-bit integer range [-2^31, 2^31 - 1], then return 0.


Example


Example 1

Input: x = 123
Output: 321

Example 2

Input: x = -123
Output: -321

Example 3

Input: x = 120
Output: 21

Solution


The problem statement is pretty straightforward. We are given an integer value x, our task is to write an algorithm that reverses this given input number. Also it is stated that the given number can be negative.


If you have gone through our palindrome number article you already know that reversing an integer value was one of the sub-tasks we had to do in our palindrome number solution. The solution to this problem is almost the same as the reversing integer part described in palindrome number solution.


This problem can be efficiently solved using the divide and mod operations. The idea is to reverse the given number by applying the divide (/) and mod (%) operations on it.


To reverse the given number we need to do the following steps:

  1. Extract last digit from right to left from the given number using