# leetcode | # | Title | Solution | Difficulty | |-|-|-|-| | [8](https://leetcode.com/problems/string-to-integer-atoi) | [String to Integer (atoi)](https://leetcode.com/problems/string-to-integer-atoi) | [Java](/solutions/string-to-integer-atoi/Solution.java) | Medium | | [5](https://leetcode.com/problems/longest-palindromic-substring) | [Longest Palindromic Substring](https://leetcode.com/problems/longest-palindromic-substring) | [Java](/solutions/longest-palindromic-substring/Solution.java) | Medium | | [1636](https://leetcode.com/problems/sort-array-by-increasing-frequency) | [Sort Array by Increasing Frequency](https://leetcode.com/problems/sort-array-by-increasing-frequency) | [Java](/solutions/sort-array-by-increasing-frequency/Solution.java) | Easy | | [1](https://leetcode.com/problems/two-sum) | [Two Sum](https://leetcode.com/problems/two-sum) | [Java](/solutions/two-sum/Solution.java) | Easy | | [1608](https://leetcode.com/problems/special-array-with-x-elements-greater-than-or-equal-x) | [Special Array With X Elements Greater Than or Equal X](https://leetcode.com/problems/special-array-with-x-elements-greater-than-or-equal-x) | [Java](/solutions/special-array-with-x-elements-greater-than-or-equal-x/Solution.java) | Easy | | [4](https://leetcode.com/problems/median-of-two-sorted-arrays) | [Median of Two Sorted Arrays](https://leetcode.com/problems/median-of-two-sorted-arrays) | [Rust (Two Pointers)](/solutions/median-of-two-sorted-arrays/src/bin/two-pointers.rs) | Hard | | [2](https://leetcode.com/problems/add-two-numbers) | [Add Two Numbers](https://leetcode.com/problems/add-two-numbers) | [Java](/solutions/add-two-numbers/Solution.java) | Medium | | [1048](https://leetcode.com/problems/longest-string-chain) | [Longest String Chain](https://leetcode.com/problems/longest-string-chain) | [Java](/solutions/longest-string-chain/Solution.java) | Medium | | [7](https://leetcode.com/problems/reverse-integer) | [Reverse Integer](https://leetcode.com/problems/reverse-integer) | [Java](/solutions/reverse-integer/Solution.java) | Medium | | [6](https://leetcode.com/problems/zigzag-conversion) | [Zigzag Conversion](https://leetcode.com/problems/zigzag-conversion) | [Java](/solutions/zigzag-conversion/Solution.java) | Medium | | [9](https://leetcode.com/problems/palindrome-number) | [Palindrome Number](https://leetcode.com/problems/palindrome-number) | [Java](/solutions/palindrome-number/Solution.java) | Easy | | [238](https://leetcode.com/problems/product-of-array-except-self) | [Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self) | [Rust](/solutions/product-of-array-except-self/src/main.rs) | Medium | | [13](https://leetcode.com/problems/roman-to-integer) | [Roman to Integer](https://leetcode.com/problems/roman-to-integer) | [Java](/solutions/roman-to-integer/Solution.java) | Easy | | [3](https://leetcode.com/problems/longest-substring-without-repeating-characters) | [Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters) | [Java](/solutions/longest-substring-without-repeating-characters/Solution.java) | Medium | | [387](https://leetcode.com/problems/first-unique-character-in-a-string) | [First Unique Character in a String](https://leetcode.com/problems/first-unique-character-in-a-string) | [Java](/solutions/first-unique-character-in-a-string/Solution.java), [Java (HashMap)](/solutions/first-unique-character-in-a-string/Solution_HashMap.java) | Easy | | [1487](https://leetcode.com/problems/making-file-names-unique) | [Making File Names Unique](https://leetcode.com/problems/making-file-names-unique) | [Java](/solutions/making-file-names-unique/Solution.java), [Java (RegEx)](/solutions/making-file-names-unique/Solution_regex.java), [Python](/solutions/making-file-names-unique/Solution.py) | Medium | | [451](https://leetcode.com/problems/sort-characters-by-frequency) | [Sort Characters By Frequency](https://leetcode.com/problems/sort-characters-by-frequency) | [Java](/solutions/sort-characters-by-frequency/Solution.java) | Medium | Generated on 2023-10-08