Given a number, check if it is power of four or not.
Given M sorted lists of variable length, print them in sorted order efficiently.
Given a string, calculate its rank among all its lexicographically sorted permutations. For example, consider below lexicographically sorted permutations
Given a linked list containing 0’s, 1’s and 2’s, sort linked list by doing single traversal of it.
Given two Boolean arrays X and Y, find the length of longest continuous sequence that starts and ends at same index in both arrays and have same sum. In other words, find max(j-i+1) for every j >= i where sum of sub-array X[i, j] is equal to sum of sub-array Y[i, j].
Implement Quicksort efficiently for inputs containing many repeated elements.
In this article, we will implement Ternary Search algorithm and compare its performance with Binary Search.
Given an integer, reverse its bits using binary operators. The idea is to initialize the result by 0 (all bits 0) and process the given number starting from its least significant bit. If the current bit is 1, then we set the corresponding most significant bit in the result and finally move on …
Given a mobile keypad having digits from [0-9] associated with each key, count total possible combinations of digits having length n. We can start with any digit and press only four adjacent keys of any digit. Keypad also contains * and # key which we are not allowed to press.
The longest common subsequence (LCS) problem is the problem of finding the longest subsequence that is present in given two sequences in the same order. i.e. find a longest sequence which can be obtained from the first original sequence by deleting some items, and from the second original sequence by deleting other items.
Huffman Coding is a algorithm for doing data compression and it forms the basic idea behind file compression. This post talks about fixed length and variable length encoding, uniquely decodable codes, prefix rules and construction of Huffman Tree.
Given a directed graph, check if it is strongly connected or not. A directed graphs is said to be strongly connected if every vertex is reachable from every other vertex.