Find the most frequent integer in an array  X

Find pairs in an integer array whose sum is equal to 10 (bonus: do it in linear time)   X

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}

Write fibbonaci iteratively and recursively (bonus: use dynamic programming)    X

Find the only element in an array that only occurs once.    

Find the common elements of 2 int arrays

Implement binary search of a sorted array of integers   X

Implement binary search in a rotated array (ex. {5,6,7,8,1,2,3})    X

Use dynamic programming to find the first X prime numbers   

Write a function that prints out the binary form of an int  X

Implement parseInt

Implement squareroot function

Implement an exponent function (bonus: now try in log(n) time)

Write a multiply function that multiples 2 integers without using *

HARD: Given a function rand5() that returns a random int between 0 and 5, implement rand7() X

HARD: Given a 2D array of 1s and 0s, count the number of "islands of 1s" (e.g. groups of connecting 1s)

Find the first non-repeated character in a String

Reverse a String iteratively and recursively

Determine if 2 Strings are anagrams

Check if String is a palindrome

Check if a String is composed of all unique characters

Determine if a String is an int or a double

HARD: Find the shortest palindrome in a String

HARD: Print all permutations of a String

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

Implement a BST with insert and delete functions

Print a tree using BFS and DFS

Write a function that determines if a tree is a BST

Find the smallest element in a BST

Find the 2nd largest number in a BST

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

Find the distance between 2 nodes in a BST and a normal binary tree

Print the coordinates of every node in a binary tree, where root is 0,0

Print a tree by levels

Given a binary tree which is a sum tree, write an algorithm to determine whether the tree is a valid sum tree

Given a tree, verify that it contains a subtree.

HARD: Find the max distance between 2 nodes in a BST.

HARD: Construct a BST given the pre-order and in-order traversal Strings

Implement a stack with push and pop functions

Implement a queue with queue and dequeue functions

Find the minimum element in a stack in O(1) time

Write a function that sorts a stack (bonus: sort the stack in place without extra memory)

Implement a binary min heap. Turn it into a binary max heap

HARD: Implement a queue using 2 stacks

Implement a linked list (with insert and delete functions)

Find the Nth element in a linked list

Remove the Nth element of a linked list

Check if a linked list has cycles

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

Check whether a link list is a palindrome

Reverse a linked list iteratively and recursively

Implement bubble sort

Implement selection sort

Implement insertion sort

Implement merge sort

Implement quick sort