All Hard Articles

Largest subarray with equal number of 0s and 1s

Given an array containing only 0s and 1s, find the largest subarray which contains equal no of 0s and 1s. The expected time complexity is… Read More

Amazon

MakeMyTrip

Morgan Stanley

Paytm

prefix-sum

Arrays

DSA

Hash

Count total set bits in first N Natural Numbers (all numbers from 1 to N)

Given a positive integer N, the task is to count the total number of set bits in binary representation of all numbers from 1 to… Read More

Amazon

Bit Magic

DSA

Palindrome Partitioning

Given a string str, a partitioning of the string is a palindrome partitioning if every sub-string of the partition is a palindrome, the task is… Read More

Amazon

palindrome

DSA

Dynamic Programming

Strings

Merge two BSTs with limited extra space

Given two Binary Search Trees(BST), print the inorder traversal of merged BSTs. Examples: Input: First BST 3 / \ 1 … Read More

Amazon

Google

Merge Sort

Microsoft

Binary Search Tree

DSA

Tree

Boyer Moore Algorithm for Pattern Searching

Pattern searching is an important problem in computer science. When we do search for a string in a notepad/word file, browser, or database, pattern searching… Read More

DSA

Pattern Searching

Strings

Longest Increasing Subsequence Size (N log N)

Given an array arr[] of size N, the task is to find the length of the Longest Increasing Subsequence (LIS) i.e., the longest possible subsequence… Read More

Amazon

Arrays

BankBazaar

Binary Search

LIS

Paytm

Samsung

subsequence

Arrays

DSA

Dynamic Programming

Finite Automata algorithm for Pattern Searching

Given a text txt[0..n-1] and a pattern pat[0..m-1], write a function search(char pat[], char txt[]) that prints all occurrences of pat[] in txt[]. You may… Read More

DSA

Pattern Searching

Egg Dropping Puzzle | DP-11

The following is a description of the instance of this famous puzzle involving N = 2 eggs and a building with K = 36 floors.Suppose… Read More

Egg-Dropping

DSA

Dynamic Programming

Find the largest BST subtree in a given Binary Tree | Set 3

Largest BST in a Binary Tree | Set 3 Method 3 (Shorter, Smarter and More Efficient) In this section, a different O(n) solution is discussed.… Read More

Amazon

D-E-Shaw

DE Shaw

Samsung

Binary Search Tree

DSA

Tree

Matrix Chain Multiplication | DP-8

Given the dimension of a sequence of matrices in an array arr[], where the dimension of the ith matrix is (arr[i-1] * arr[i]), the task… Read More

Amazon

matrix-chain-multiplication

Microsoft

DSA

Dynamic Programming

Matrix

C Program for Matrix Chain Multiplication | DP-8

Write a C program for a given dimension of a sequence of matrices in an array arr[], where the dimension of the ith matrix is… Read More

C Programs

Sorted Linked List to Balanced BST

Given a Singly Linked List which has data members sorted in ascending order. Construct a Balanced Binary Search Tree which has same data members as… Read More

Binary Search Tree

DSA

Linked List

Connect nodes at same level using constant extra space

Write a function to connect all the adjacent nodes at the same level in a binary tree. The structure of the given Binary Tree node… Read More

Adobe

Amazon

Boomerang Commerce

Flipkart

Google

Microsoft

Ola Cabs

Oracle

OYO Rooms

Xome

DSA

Tree

Simulating final Class in C++

Ever wondered how can you design a class in C++ which can’t be inherited. Java and C# programming languages have this feature built-in. You can… Read More

C Language

C++

Advanced C++ | Virtual Copy Constructor

In the virtual constructor idiom we have seen the way to construct an object whose type is not determined until runtime. Is it possible to create… Read More

C Language

C++

Find Median from Running Data Stream

Given that integers are read from a data stream. Find the median of elements read so far in an efficient way. There are two cases… Read More

Adobe

Amazon

Apple

array-stream

Belzabar

Facebook

FactSet

Google

Hike

MAQ Software

median-finding

Microsoft

Morgan Stanley

Ola Cabs

Oracle

SAP Labs

statistical-algorithms

Yahoo

DSA

Heap

Mathematical

Advanced C++ | Virtual Constructor

Can we make a class constructor virtual in C++ to create polymorphic objects? No. C++ being a statically typed (the purpose of RTTI is different) language, it… Read More

C Language

C++

Subset Sum Problem using Backtracking

Given a set[] of non-negative integers and a value sum, the task is to print the subset of the given set whose sum is equal… Read More

Adobe

Amazon

Drishti-Soft

subset

Backtracking

DSA

C / C++ Program for Subset Sum | Backtracking-4

Write a C/C++ program for a given set[] of non-negative integers and a value sum, the task is to print the subset of the given… Read More

C Programs

C Program for N Queen Problem | Backtracking-3

The N Queen is the problem of placing N chess queens on an N×N chessboard so that no two queens attack each other. For example,… Read More

C Programs