| Coloring A Border | Medium | booking | |
| Compact Object | Medium | | |
| Compare Strings by Frequency of the Smallest Character | Medium | google
oracle | |
| Complete Binary Tree Inserter | Medium | amazon
google | |
| Complex Number Multiplication | Medium | amazon | |
| Concatenation of Array | Easy | | |
| Construct 2D Grid Matching Graph Layout | Hard | | |
| Construct the Lexicographically Largest Valid Sequence | Medium | | |
| Construct the Rectangle | Easy | | |
| Contiguous Array | Medium | adobe
amazon
apple
facebook
google
microsoft
quora
robinhood
vmware | |
| Convert Binary Number in a Linked List to Integer | Easy | cisco
roblox
servicenow | |
| Convert Date to Binary | Easy | | |
| Convert Integer to the Sum of Two No-Zero Integers | Easy | hrt | |
| Coordinate With Maximum Network Quality | Medium | | |
| Corporate Flight Bookings | Medium | goldman-sachs | |
| Count Almost Equal Pairs I | Medium | | |
| Count Alternating Subarrays | Medium | | |
| Count Array Pairs Divisible by K | Hard | | |
| Count Asterisks | Easy | | |
| Count Beautiful Substrings I | Medium | | |
| Count Beautiful Substrings II | Hard | | |
| Count Binary Substrings | Easy | helix | |
| Count Collisions of Monkeys on a Polygon | Medium | | |
| Count Days Spent Together | Easy | | |
| Count Distinct Numbers on Board | Easy | | |
| Count Elements With Maximum Frequency | Easy | | |
| Count Elements With Strictly Smaller and Greater Elements | Easy | | |
| Count Fertile Pyramids in a Land | Hard | | |
| Count Hills and Valleys in an Array | Easy | | |
| Count Increasing Quadruplets | Hard | | |
| Count Integers in Intervals | Hard | | |
| Count Integers With Even Digit Sum | Easy | | |
| Count Items Matching a Rule | Easy | | |
| Count K-Reducible Numbers Less Than N | Hard | | |
| Count K-Subsequences of a String With Maximum Beauty | Hard | | |
| Count Nodes Equal to Average of Subtree | Medium | | |
| Count Number of Possible Root Nodes | Hard | | |
| Count Number of Special Subsequences | Hard | | |
| Count Number of Texts | Medium | | |
| Count Number of Ways to Place Houses | Medium | | |
| Count of Matches in Tournament | Easy | | |
| Count of Sub-Multisets With Bounded Sum | Hard | | |
| Count of Substrings Containing Every Vowel and K Consonants 2 | Medium | | |
| Count Operations to Obtain Zero | Easy | | |
| Count Pairs of Connectable Servers in a Weighted Tree Network | Medium | | |
| Count Pairs Of Nodes | Hard | | |
| Count Pairs of Points With Distance k | Medium | | |
| Count Pairs That Form a Complete Day I | Easy | | |
| Count Pairs That Form a Complete Day II | Medium | | |
| Count Paths That Can Form a Palindrome in a Tree | Hard | | |