Algorithms

1. (Difficulty: 3) Merge Sort Time Complexity: O(n log(n))

2. (Difficulty: 3) Quick Sort Time Complexity: O(n log(n))

3. (Difficulty: 3) Heap Sort Time Complexity: O(n log(n))

3. (Difficulty: 4) Rabin-Karp Algorithm

4. (Difficulty: 5) Knuth-Morris-Pratt(KMP) Algorithm

5. (Difficulty: 4) Dijkstra's Algorithm

6. (Difficulty: 3) Kadane's Algorithm Time Complexity: O(n)

Data Structures

1. (Difficulty: 2) Binary Search Tree

2. (Difficulty: 3) Optimal Binary Search Tree

3. (Difficulty: 2) Trie

4. (Difficulty: 3) Max Heap

Problems

1. (Difficulty: 3) Find the best apartment block on a single lane street based on minimum maximum distance to any of the required buildings.

2. (Difficulty: 4) Find all permutations of a small string which exist in a larger string.

3. (Difficulty: 4) Given an array of integers and a target integer, check if any subset elements of the array can add up to the target. (Subset Problem)

Arrays & Strings

1. (Difficulty: 2) Find intersection of two sorted array of integers. Time Complexity: O(n)

2. (Difficulty: 3) Alphabetize (sort alphabetically) lowercase characters in a given string. Time Complexity: O(n log(n))

3. (Difficulty: 3) Given two arrays of keypresses, determine if they output same printable string. Time Complexity: O(n)

4. (Difficulty: 2) Hexadecimal string addition. Time Complexity: O(n)

5. (Difficulty: 3) Rearrange given characters so that same character does not occur more than once in a given window. Time Complexity: O(n)

6. (Difficulty: 3) Search a number in a sorted circular rotated array.

7. (Difficulty: 4) Find words whose number representation are substring of a given number.

8. (Difficulty: 3) Determine if an input string can be segmented into words from a given list of words.

9. (Difficulty: 3) Given a number string, find the number of ways it can be converted to english alphabet words for a one to one mapping between alphabets and numbers.

10. (Difficulty: 3) Count minimum adjacent swaps required to make a palindrome

11. (Difficulty: 3) Find minimum possible amplitude of a given integer array

Trees

1. (Difficulty: 2) Invert/Flip/Mirror a binary tree

Bit manipulation

1. (Difficulty: 3) Pending - Swap two bits in a given unsigned long integer.

Grids & Matrices

1. (Difficulty: 3) Count the number of islands in a 2d grid.

2. (Difficulty: 3) Given a list of coordinates in a 2D plane, count number of rectangles that can be created whose edges are aligned to the two axes.

Named Problems

1. (Difficulty: 4) 0-1 Knapsack problem

2. (Difficulty: 3) Dutch National Flag (DNF) Sort

Design

1. (Difficulty: 2) Design class with insert, random peek and random delete capabilities.