michaltakac / java-programming-questions

Beginner, learning algorithms and shit. Just for fun.

Programming Questions

Solving programming questions, just for fun. https://www.reddit.com/r/cscareerquestions/comments/20ahfq/heres_a_pretty_big_list_of_programming_interview/

I'm not currently studying for an interview, but I like to learn. I did not study CS but I'm interested in algorithms.

Table of contents

General

1. Find the most frequent integer in an array
2. Find pairs in an integer array whose sum is equal to 10 (bonus: do it in linear time)
3. Given 2 integer arrays, determine of the 2nd array is a rotated version of the 1st array. Ex. Original Array A={1,2,3,5,6,7,8} Rotated Array B={5,6,7,8,1,2,3}
4. Write fibbonaci iteratively and recursively (bonus: use dynamic programming)
5. Find the only element in an array that only occurs once.
6. Find the common elements of 2 int arrays
7. Implement binary search of a sorted array of integers
8. Implement binary search in a rotated array (ex. {5,6,7,8,1,2,3})
9. Use dynamic programming to find the first X prime numbers
10. Write a function that prints out the binary form of an int
11. Implement parseInt
12. Implement squareroot function
13. Implement an exponent function (bonus: now try in log(n) time)
14. Write a multiply function that multiples 2 integers without using *
15. HARD: Given a function rand5() that returns a random int between 0 and 5, implement rand7()
16. HARD: Given a 2D array of 1s and 0s, count the number of "islands of 1s" (e.g. groups of connecting 1s)

Strings

1. Find the first non-repeated character in a String
2. Reverse a String iteratively and recursively
3. Determine if 2 Strings are anagrams
4. Check if String is a palindrome
5. Check if a String is composed of all unique characters
6. Determine if a String is an int or a double
7. HARD: Find the shortest palindrome in a String
8. HARD: Print all permutations of a String
9. HARD: Given a single-line text String and a maximum width value, write the function 'String justify(String text, int maxWidth)' that formats the input text using full-justification, i.e., extra spaces on each line are equally distributed between the words; the first word on each line is flushed left and the last word on each line is flushed right

Trees

1. Implement a BST with insert and delete functions
2. Print a tree using BFS and DFS
3. Write a function that determines if a tree is a BST
4. Find the smallest element in a BST
5. Find the 2nd largest number in a BST
6. Given a binary tree which is a sum tree (child nodes add to parent), write an algorithm to determine whether the tree is a valid sum tree
7. Find the distance between 2 nodes in a BST and a normal binary tree
8. Print the coordinates of every node in a binary tree, where root is 0,0
9. Print a tree by levels
10. Given a binary tree which is a sum tree, write an algorithm to determine whether the tree is a valid sum tree
11. Given a tree, verify that it contains a subtree.
12. HARD: Find the max distance between 2 nodes in a BST.
13. HARD: Construct a BST given the pre-order and in-order traversal Strings

Stacks, Queues, and Heaps

1. Implement a stack with push and pop functions
2. Implement a queue with queue and dequeue functions
3. Find the minimum element in a stack in O(1) time
4. Write a function that sorts a stack (bonus: sort the stack in place without extra memory)
5. Implement a binary min heap. Turn it into a binary max heap
6. HARD: Implement a queue using 2 stacks

Linked Lists

1. Implement a linked list (with insert and delete functions)
2. Find the Nth element in a linked list
3. Remove the Nth element of a linked list
4. Check if a linked list has cycles
5. Given a circular linked list, find the node at the beginning of the loop. Example: A-->B-->C --> D-->E -->C, C is the node that begins the loop
6. Check whether a link list is a palindrome
7. Reverse a linked list iteratively and recursively

Sorting

1. Implement bubble sort
2. Implement selection sort
3. Implement insertion sort
4. Implement merge sort
5. Implement quick sort

License

MIT