| Count Prefix and Suffix Pairs 2 | Hard | | |
| Count Special Quadruplets | Easy | | |
| Count Stepping Numbers in Range | Hard | | |
| Count Substrings Starting and Ending with Given Character | Medium | | |
| Count Substrings That Differ by One Character | Medium | | |
| Count Substrings That Satisfy K-Constraint I | Easy | | |
| Count Subtrees With Max Distance Between Cities | Hard | | |
| Count Symmetric Integers | Easy | | |
| Count the Number of Houses at a Certain Distance II | Hard | | |
| Count the Number of Incremovable Subarrays I | Easy | | |
| Count the Number of Special Characters I | Easy | | |
| Count the Number of Special Characters II | Medium | | |
| Count the Number of Square-Free Subsets | Medium | | |
| Count the Number of Substrings With Dominant Ones | Medium | | |
| Count The Number of Winning Sequences | Hard | | |
| Count Unhappy Friends | Medium | | |
| Count Unique Characters of All Substrings of a Given String | Hard | forusall
microsoft
twitch | |
| Count Visited Nodes in a Directed Graph | Hard | | |
| Count Vowel Substrings of a String | Easy | | |
| Count Words Obtained After Adding a Letter | Medium | | |
| Count Zero Request Servers | Medium | | |
| Counter | Easy | | |
| Counter II | Easy | | |
| Couples Holding Hands | Hard | amazon
google
spotify | |
| Course Schedule 4 | Medium | uber | |
| Create a DataFrame from List | Easy | | |
| Create a New Column | Easy | | |
| Create Hello World Function | Easy | | |
| Cyclically Rotating a Grid | Medium | | |
| Day of the Week | Easy | microsoft
united-health-group | |
| Decode the Message | Easy | | |
| Decrease Elements To Make Array Zigzag | Medium | google | |
| Decrypt String from Alphabet to Integer Mapping | Easy | quip | |
| Defanging an IP Address | Easy | adobe
amazon
apple
facebook
google
yahoo | |
| Degree of an Array | Easy | citrix
ge-digital
ixl
mathworks
robinhood
visa
vmware | |
| Delete Columns to Make Sorted II | Medium | google | |
| Delete Duplicate Folders in System | Hard | | |
| Describe the Painting | Medium | | |
| Design a Text Editor | Hard | | |
| Design Authentication Manager | Medium | | |
| Design Bitset | Medium | | |
| Design Linked List | Medium | amazon
microsoft
oracle | |
| Design Memory Allocator | Medium | | |
| Design Movie Rental System | Hard | | |
| Design Neighbor Sum Service | Easy | | |
| Destroying Asteroids | Medium | | |
| Detect Pattern of Length M Repeated K or More Times | Easy | | |
| Determine the Winner of a Bowling Game | Easy | | |
| Determine Whether Matrix Can Be Obtained By Rotation | Easy | | |
| Difference Between Element Sum and Digit Sum of an Array | Easy | | |