// practice ground
| # | Title | Topics | Difficulty |
|---|---|---|---|
| 251 | Find the Middle Character |
Strings
|
Easy |
| 252 | Count Occurrences of a Substring |
Strings
|
Easy |
| 253 | Remove Duplicate Characters |
Hashing
Strings
|
Easy |
| 254 | Sort Characters by Frequency |
Hashing
Sorting
Strings
|
Medium |
| 255 | Find the Difference Between Two Strings |
Hashing
Strings
|
Easy |
| 256 | Check if String Contains All Unique Characters |
Hashing
Strings
|
Easy |
| 257 | Find All Substrings of a String |
Loops
Strings
|
Easy |
| 258 | String to Integer (atoi) |
Math
Strings
|
Medium |
| 259 | Integer to Roman |
Math
Strings
|
Medium |
| 260 | Roman to Integer |
Math
Strings
|
Easy |
| 261 | Count and Say |
Simulation
Strings
|
Medium |
| 262 | Decode Ways |
Dynamic Programming
Strings
|
Medium |
| 263 | Wildcard Matching |
Dynamic Programming
Strings
|
Hard |
| 264 | Regular Expression Matching |
Dynamic Programming
Strings
|
Hard |
| 265 | Minimum Window Substring |
Hashing
Sliding Window
Strings
|
Hard |
| 266 | Find All Anagrams in a String |
Hashing
Sliding Window
Strings
|
Medium |
| 267 | Longest Repeating Character Replacement |
Sliding Window
Strings
|
Medium |
| 268 | Multiply Strings |
Math
Strings
|
Medium |
| 269 | Decode String |
Stacks
Strings
|
Medium |
| 270 | Remove K Digits |
Greedy
Stacks
Strings
|
Medium |
| 271 | Find Pivot Index |
Arrays
|
Easy |
| 272 | Largest Number At Least Twice of Others |
Arrays
|
Easy |
| 273 | Plus One |
Arrays
Math
|
Easy |
| 274 | Array Partition |
Arrays
Greedy
Sorting
|
Easy |
| 275 | Can Place Flowers |
Arrays
Greedy
|
Easy |
