| # | Title | Solution | Difficulty |
|---|---|---|---|
| 1 | Two Sum | JavaScript | Easy |
| 15 | 3Sum | JavaScript | Medium |
| 16 | 3Sum Closest | Medium | |
| 18 | 4Sum | JavaScript | Medium |
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 175 | Combine Two Tables | SQL | Easy |
| 176 | Second Highest Salary | SQL | Easy |
| 177 | Nth Highest Salary | SQL | Medium |
| 178 | Rank Scores | SQL | Medium |
| 180 | Consecutive Numbers | SQL | Medium |
| 181 | Employees Earning More Than Their Managers | SQL | Easy |
| 182 | Duplicate Emails | SQL | Easy |
| 183 | Customers Who Never Order | SQL | Easy |
| 184 | Department Highest Salary | SQL | Medium |
| 185 | Department Top Three Salaries | SQL | Hard |
| 196 | Delete Duplicate Emails | SQL | Easy |
| 197 | Rising Temperature | SQL | Easy |
| 262 | Trips and Users | SQL | Hard |
| 595 | Big Countries | SQL | Easy |
| 596 | Classes More Than 5 Students | SQL | Easy |
| 601 | Human Traffic of Stadium | SQL | Hard |
| 620 | Not Boring Movies | SQL | Easy |
| 626 | Exchange Seats | SQL | Medium |
| 627 | Swap Salary | SQL | Easy |