| # | Title | Solution | Difficulty |
|---|---|---|---|
| 1 | Two Sum | Ruby | Easy |
| 2 | Add Two Numbers | Ruby | Medium |
| 3 | Longest Substring Without Repeating Characters | Ruby | Medium |
| 4 | Median of Two Sorted Arrays | Ruby | Hard |
| 6 | Verifying an Alien Dictionary | Ruby | Medium |
| 9 | Palindrome Number | Ruby | Easy |
| 10 | Regular Expression Matching | Ruby | Hard |
| 13 | Roman to Integer | Ruby | Easy |
| 14 | Longest Common Prefix | Ruby | Easy |
| 20 | Valid Parentheses | Ruby | Easy |
| 21 | Merge Two Sorted Lists | Ruby | Easy |
| 23 | Merge k Sorted Lists | Ruby | Hard |
| 26 | Remove Duplicates from Sorted Array | Ruby | Easy |
| 27 | Remove Element | Ruby | Easy |
| 28 | Find the Index of the First Occurrence in a String | Ruby | Medium |
| 35 | Search Insert Position | Ruby | Easy |
| 45 | Jump Game II | Ruby | Medium |
| 58 | Length of Last Word | Ruby | Easy |
| 66 | Plus One | Ruby | Easy |
| 67 | Add Binary | Ruby Python3 | Easy |
| 69 | Sqrt(x) | Ruby | Easy |
| 70 | Climbing Stairs | Ruby | Easy |
| 72 | Edit Distance | Ruby | Hard |
| 91 | Decode Ways | Ruby | Medium |
| 103 | Binary Tree Zigzag Level Order Traversal | Ruby | Medium |
| 104 | Maximum Depth of Binary Tree | Ruby Python3 | Easy |
| 109 | Convert Sorted List to Binary Search Tree | Ruby | Medium |
| 113 | Path Sum II | Ruby | Medium |
| 121 | Best Time to Buy and Sell Stock | Ruby | Easy |
| 142 | Linked List Cycle II | Ruby | Medium |
| 226 | Invert Binary Tree | Ruby | Easy |
| 344 | Reverse String | Ruby | Easy |
| 382 | Linked List Random Node | Ruby | Medium |
| 387 | First Unique Character in a String | Ruby | Easy |
| 427 | Construct Quad Tree | Ruby | Medium |
| 438 | Find All Anagrams in a String | Ruby | Medium |
| 443 | String Compression | Ruby Python3 | Medium |
| 502 | IPO | Ruby Python3 | Hard |
| 509 | Fibonacci Number | Ruby | Easy |
| 540 | Single Element in a Sorted Array | Ruby | Medium |
| 557 | Reverse Words in a String III | Ruby | Easy |
| 567 | Permutation in String | Ruby | Medium |
| 622 | Design Circular Queue | Ruby | Medium |
| 652 | Find Duplicate Subtrees | Ruby | Medium |
| 733 | Flood Fill | Ruby | Easy |
| 783 | Minimum Distance Between BST Nodes | Ruby Python3 | Easy |
| 875 | Koko Eating Bananas | Ruby Python3 | Medium |
| 904 | Fruit Into Baskets | Ruby | Medium |
| 912 | Sort an Array | Ruby | Medium |
| 953 | Verifying an Alien Dictionary | Ruby | Easy |
| 989 | Add to Array-Form of Integer | Ruby | Easy |
| 990 | Satisfiability of Equality Equations | Ruby | Medium |
| 1011 | Capacity To Ship Packages Within D Days | Ruby | Medium |
| 1071 | Greatest Common Divisor of Strings | Ruby | Easy |
| 1129 | Shortest Path with Alternating Colors | Ruby | Medium |
| 1155 | Number of Dice Rolls With Target Sum | Ruby | Medium |
| 1162 | As Far from Land as Possible | Ruby | Medium |
| 1345 | Jump Game IV | Ruby | Hard |
| 1470 | Shuffle the Array | Ruby | Easy |
| 1523 | Count Odd Numbers in an Interval Range | Ruby | Easy |
| 1539 | Kth Missing Positive Number | Ruby | Easy |
| 1675 | Minimize Deviation in Array | Ruby | Hard |
| 1680 | Concatenation of Consecutive Binary Numbers | Ruby | Medium |
| 2187 | Minimum Time to Complete Trips | Ruby Python3 | Medium |
| 2409 | Count Days Spent Together | Ruby | Easy |
| 2413 | Smallest Even Multiple | Ruby | Easy |
| 2444 | Count Subarrays With Fixed Bounds | Ruby | Hard |
| 2477 | Minimum Fuel Cost to Report to the Capital | Ruby | Medium |
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 175 | Combine Two Tables | Database | Easy |
| 181 | Employees Earning More Than Their Managers | Database | Easy |
| 182 | Duplicate Emails | Database | Easy |
| 183 | Customers Who Never Order | Database | Easy |
| 196 | Delete Duplicate Emails | Database | Easy |
| 197 | Rising Temperature | Database | Easy |
| 584 | Find Customer Referee | Database | Easy |
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 192 | Word Frequency | Shell | Medium |
| 193 | Valid Phone Numbers | Shell | Easy |
| 194 | Transpose File | Shell | Medium |
| 195 | Tenth Line | Shell | Easy |