Add Reverse Integer

Author: thanthtooaung-coding

README.md

@@ -6,7 +6,7 @@ This repository contains my solutions to various LeetCode problems. Each solutio
 
 ## LeetCode Stats
 - **Profile**: [Vinnn_96](https://leetcode.com/u/Vinnn_96/)
-- **Problems Solved**: 8
+- **Problems Solved**: 9
 - **Languages**: Java
 
 ## Repository Structure
@@ -25,14 +25,15 @@ Each problem has its own directory containing:
 | 4 | [Median of Two Sorted Arrays](Median%20of%20Two%20Sorted%20Arrays) | Hard | [Java](Median%20of%20Two%20Sorted%20Arrays/Solution.java) | Array, Binary Search, Divide and Conquer |
 | 5 | [Longest Palindromic Substring](Longest%20Palindromic%20Substring) | Medium | [Java](Longest%20Palindromic%20Substring/Solution.java) | Two Pointers, String, Dynamic Programming |
 | 6 | [Zigzag Conversion](Zigzag%20Conversion) | Medium | [Java](Zigzag%20Conversion/Solution.java) | String |
+| 7 | [Reverse Integer](Reverse%20Integer) | Medium | [Java](Reverse%20Integer/Solution.java) | Math |
 | 214 | [Shortest Palindrome](Shortest%20Palindrome) | Hard | [Java](Shortest%20Palindrome/Solution.java) | String, Rolling Hash, String Matching, Hash Function |
 | 2924 | [Find Champion II](Find%20Champion%20II) | Medium | [Java](Find%20Champion%20II/Solution.java) | Graph |
 
 ## Categories
 
 ### By Difficulty
 - Easy: 1
-- Medium: 5
+- Medium: 6
 - Hard: 2
 
 ### By Topics
@@ -59,6 +60,8 @@ Each problem has its own directory containing:
   - [Find Champion II](Find%20Champion%20II)
 - String Matching Problems
   - [Shortest Palindrome](Shortest%20Palindrome)
+- Math Problems
+  - [Reverse Integer](Reverse%20Integer)
 
 ## About LeetCode
 

Reverse Integer/README.md

@@ -0,0 +1,35 @@
+# Reverse Integer
+
+## LeetCode Problem
+- Problem Number: 7
+- Problem Link: https://leetcode.com/problems/reverse-integer/
+- Difficulty: Medium
+- Topics: Math
+
+## Problem 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).
+
+## Examples
+
+### 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

Reverse Integer/Solution.java

@@ -0,0 +1,23 @@
+class Solution {
+    public int reverse(int x) {
+        int INT_MIN = -2147483648;
+        int INT_MAX = 2147483647;
+
+        int result = 0;
+
+        while (x != 0) {
+            int digit = x % 10;
+            x /= 10;
+
+            if (result > (INT_MAX / 10) || (result == INT_MAX / 10 && digit > 7)) {
+                return 0;
+            }
+            if (result < (INT_MIN / 10) || (result == INT_MIN / 10 && digit < -8)) {
+                return 0;
+            }
+
+            result = result * 10 + digit;
+        }
+        return result;
+    }    
+}