These are my solutions to some of the 100 coding interview questions listed here. Unless they are answers to design questions, the solutions are implemented in Swift.
Some of the callenges occur twice. I just did them twice to get more exercise. Sometime the solution is the same, sometimes it's a different one.
I am happy for any feedback or pull request.
You can run each individual file with this command:
swift <filename>If you want to run all the tests with all the files, just use the bash script
./run_tests.shThe original list lists the challenges unordered. To give a better overview, I sorted them according to topics:
Sorting
- Bubble sort (1.)
- Merge sort (2., 98.)
- Bucket sort (6.)
- Counting sort (7.)
- Radix sort (11.)
- Difference between stable and unstable sorting algorithm (18., 94.)
- Quicksort (19., 29., 96.)
- Insertion sort (25., 97.)
- Difference Comparison and Non-Comparison sort
Arrays
- Removing duplicates (8., 10., 26.)
- Reversing arrays (9.)
- Find missing number in array 1 to 100 (15.)
- Finding duplicate (16., 17.)
- Find smallest and largest number in unsorted array (20.)
- Finding pairs of integers with special sum (24.)
- Binary search in array (71.)
- Binary search without recursion (93.)
LinkedLists
- Reverse linkedlist inplace (21., 50., 51.)
- Add element to middle of linked list (22.)
- Sort a linked list (23.)
- Remove n-th node from end (39.)
- Merge two sorted lists (40.)
- Convert sorted list to binary search tree (41.)
- Find middle of linked list (48.)
- Check for cycle and find beginning (49.)
- Remove duplicates from unsorted list (52.)
- Remove duplicates from sorted list (57.)
- Remove specific values from a linked list (61.)
- Length of singly linked list (53.)
- Third node from end of linked list (54.)
- Sum of two linked lists (55.)
- Difference array and linked list (56.)
- Find node at intersection of two linked lists (58.)
- Partition linked list according to x (59.)
- Check linked list for palindrome (60.)
Trees
- Convert sorted list to binary search tree (41.)
- Implementation of a binary search tree (62.)
- Preorder traversal (63., 64.)
- Inorder traversal (65., 66.)
- Postorder traversal (67., 68.)
- Print all leaves of BST (69.)
- Count number of leaves (70.)
- Depth First Search (95.)
String
- Counting char occurences (3.)
- Printing first non-repeated chars (4.)
- Converting string to int (5.)
- Remove duplicate char from string (27.)
- Find maximum occurring char (28.)
- Reverse a string (30., 34.)
- Find duplicate chars in string (31.)
- Check if strings are anagrams (32.)
- Find all permutations of a string (33.)
- Check for palindrome (35.)
- Longest non-repeating substring (36.)
- Longest palindromic substring (37.)
- Check for string with only digits (38.)
- Count vowels and consonants in a string (43.)
- Reverse words in a sentence (44.)
- Check if two strings are a rotation (45.)
- Convert byte array to string (46.)
- Replace char (47.)
Numbers
- Check if number is palindrome (76.)
- Check if number is Armstrong number (77.)
- Find all prime factors of a number (78.)
- Check if number is positive/negative (79.)
- Find largest prime factor of given number (80.)
- Print all primes up to a number (81.)
- Floyd's trianlge (82.)
- Pascal's triangle (83.)
- Calculate square root (84.)
- Check if a number is a prime (85.)
- Add two numbers without using arithmetic operators (86.)
- Check if number is even/odd without using arithmetic operators (87.)
- Reverse an Integer (90.)
- Convert decimal to binary (91.)
- Sieve of Eratosthenes (100.)
Mixed
- Check if two rectangles overlap (13., 73.)
- Desing a vending machine (14., 74.)
- Swap number without using a third variable (12., 72.)
- Implement an LRU cache (75.)
- Find highest repeating word in a file (89.)
- Pyramid structure (88.)
- Check lap year (92.)