| Reverse String | Open ↗ |
| Reverse String II | Open ↗ |
| Reverse String Prefix | Open ↗ |
| Reverse Substrings Between Each Pair of Parentheses | Open ↗ |
| Reverse the array | Open ↗ |
| Reverse the first “K” elements of a queue | Open ↗ |
| Reverse Vowels of a String | Open ↗ |
| Reverse words in a given string | Open ↗ |
| Reverse Words in a String | Open ↗ |
| Reverse Words in a String II | Open ↗ |
| Reverse Words in a String III | Open ↗ |
| Reward Top K Students | Open ↗ |
| Richest Customer Wealth | Open ↗ |
| Right Triangles | Open ↗ |
| Right View of Tree | Open ↗ |
| Rings and Rods | Open ↗ |
| Rising Temperature | Open ↗ |
| RLE Iterator | Open ↗ |
| Robot Bounded In Circle | Open ↗ |
| Robot Collisions | Open ↗ |
| Robot Return to Origin | Open ↗ |
| Robot Room Cleaner | Open ↗ |
| Rod Cutting | Open ↗ |
| Rod cutting problem | Open ↗ |
| Roman Number to Integer | Open ↗ |
| Roman to Integer | Open ↗ |
| Root Equals Sum of Children | Open ↗ |
| Root to leaf paths sum | Open ↗ |
| Rope Cutting | Open ↗ |
| Rotate a Doubly Linked list in group of Given Size.[Very IMP] | Open ↗ |
| Rotate a Linked List | Open ↗ |
| Rotate Array | Open ↗ |
| Rotated Digits | Open ↗ |
| Rotate DoublyLinked list by N nodes. | Open ↗ |
| Rotate Function | Open ↗ |
| Rotate Image | Open ↗ |
| Rotate List | Open ↗ |
| Rotate matrix by 90 degrees | Open ↗ |
| Rotate Non Negative Elements | Open ↗ |
| Rotate String | Open ↗ |
| Rotating the Box | Open ↗ |
| ROTI-Prata SPOJ | Open ↗ |
| Rotten-oranges | Open ↗ |
| Rotting Oranges | Open ↗ |
| Row With Maximum Ones | Open ↗ |
| Running Sum of 1d Array | Open ↗ |
| Russian Doll Envelopes | Open ↗ |
| Sales Analysis I | Open ↗ |
| Sales Analysis II | Open ↗ |
| Sales Analysis III | Open ↗ |
| Sales by Day of the Week | Open ↗ |
| Sales Person | Open ↗ |
| Same Tree | Open ↗ |
| Satisfiability of Equality Equations | Open ↗ |
| Score After Flipping Matrix | Open ↗ |
| Score of a String | Open ↗ |
| Score of Parentheses | Open ↗ |
| Scrambled String | Open ↗ |
| Scramble String | Open ↗ |
| Search a 2D Matrix | Open ↗ |
| Search a 2D Matrix II | Open ↗ |
| Search an Element in an array | Open ↗ |
| Search a node in BST | Open ↗ |
| Search a Word in a 2D Grid of characters. | Open ↗ |
| Search in a Binary Search Tree | Open ↗ |
| Search in a matrix | Open ↗ |
| Search in a row-column sorted Matrix | Open ↗ |
| Search in a Sorted Array of Unknown Size | Open ↗ |
| Searching an element in a sorted array | Open ↗ |
| Searching in an array where adjacent differ by at most k | Open ↗ |
| Search in Rotated Sorted Array | Open ↗ |
| Search in Rotated Sorted Array II | Open ↗ |
| Search Insert Position | Open ↗ |
| Search Suggestions System | Open ↗ |
| Seat Reservation Manager | Open ↗ |
| Seats | Open ↗ |
| Second Highest Occurring Element | Open ↗ |
| Second Highest Salary | Open ↗ |
| Second Largest Digit in a String | Open ↗ |
| Second Largest Element | Open ↗ |
| Second Minimum Node In a Binary Tree | Open ↗ |
| Second Minimum Time to Reach Destination | Open ↗ |
| Segregate even and odd Elements in a Linked List | Open ↗ |
| Segregate even and odd nodes in a Linked List | Open ↗ |
| Select Data | Open ↗ |
| Selection Sort | Open ↗ |
| Selection Sort | Open ↗ |
| Select K Disjoint Special Substrings | Open ↗ |
| Self Crossing | Open ↗ |
| Self Dividing Numbers | Open ↗ |
| Sell Diminishing-Valued Colored Balls | Open ↗ |
| Sender With Largest Word Count | Open ↗ |
| Sentence Screen Fitting | Open ↗ |
| Sentence Similarity | Open ↗ |
| Sentence Similarity II | Open ↗ |
| Sentence Similarity III | Open ↗ |
| Separate Black and White Balls | Open ↗ |
| Separate Squares I | Open ↗ |
| Separate Squares II | Open ↗ |
| Separate the Digits in an Array | Open ↗ |