> Data Structures and Algorithms (DSA) Interview Questions

Data Structures and Algorithms (DSA) Interview Questions

Data Structures and Algorithms (DSA) Interview Questions to learn data structures and algorithms for job interview questions and improve your problem solving skills to provide efficient solution to complex problems.

The best way to learn data structures and algorithms will be learn the concepts, implement it, solve the problems using concepts and then write the program in programming language you love most. [DSA Roadmap]

Recommended Book :
Comprehensive Data Structures and Algorithms in Java
Comprehensive Data Structures and Algorithms in C++

CourseGalaxy Problem Set 107

First learn the data Structures and Algorithms and implement it. Then move to problems. [DSA Roadmap] There are 107 problems in this CourseGalaxy Problem Set 107.

Arrays

Reverse the elements of an array.
Rotate left an array by k elements.

Solutions

2 loops
Reverse of array elements

reverse(arr, 0, k-1);
reverse(arr, k, n-1);
reverse(arr, 0, n-1);

Pascal's triangle.
Remove duplicate elements from an unsorted array.

Solutions

2 loops
Sort it and then traverse to remove duplicates
Hashing
BST, remove duplicates while insertion

Leaders in an array
Sliding window maximum
Rotate a matrix 90 degree
Majority elements
Product of array except self
Inversions in an array
Print a square matrix spirally.
Merge two sorted arrays without extra space
Left side sum of array elements equal to right side sum

Strings

Reverse the letters in the words of a string.
Find the first non-repeating character in a string.
Longest substring without repeating characters
Print all permutations of a given string
Change the string to be in alphabetical order
Integer to roman
Longest palindrome in a string
Rotate left string1 k times to match with staring2

Linked List

Reverse a linked list.
Find out the middle node of a single linked list.
Find the nth node from the end of a single linked list.
Rotate the list left by k nodes
Insert a node just before and just after a node pointed to by a pointer p, without using the pointer start.
Exchange the pair in a single linked list
Find the merge point of two single linked list (Y type).
Insert, detect, remove a cycle in linked list.
Intersection of two single linked lists (elements common to both the lists).
Union of two single linked lists (element included only once).
Reorder list
Copy list with random pointers

Stacks and Queues

Reverse a string
Implement 2 stack in an array
Min Stack
Implement 2 queue in an array
Evaluation of postfix
Valid parentheses
Largest rectangle In histogram
Next greater element

Recursion

Program to find the factorial of a number using recursion.
Summation of numbers from 1 to n
Displaying numbers from 1 to n
Display and find out the sum of series 1 + 2 + 3 + 4 + 5 +.......
Display digits of an integer number and finds the sum of digits of that number
Convert a positive decimal number to Binary, Octal or //Hexadecimal
Find the exponentiation of a number (a power n, example 2 power 3 = 8)
Display the prime factors of a number

Trees

Level order traversal of a binary tree
Height of a binary tree
K-th smallest element in a binary search tree
Check if a binary tree is BST or not
Find minimum and maximum in binary search tree.
Construct binary tree from postorder and inorder traversal
Check if two trees are identical or not
Find the inorder predecessor/successor of a given Key in BST

Graphs

Number of connected components in a directed graph
Clone a graph
Detect cycle in a directed graph
Strongly connected components
Is the graph Bipartite?
Find if a graph is strongly connected or not
Number of islands
Course schedule

Sorting, Searching, Hashing

Search in a rotated sorted array
Design hashmap
Search a 2D matrix
Partition an array such that all the even numbers are on the left side of array and odd numbers on the right side.
Find the k-th smallest element in an array.
Count negative numbers in a sorted matrix
Maximum consecutive ones
Divide two integers

Heap

K-th largest element
Top k most frequent elements
Merge k sorted arrays
Merge k sorted linked lists
Find median from data stream

Trie

Implement trie - insertion, search, deletion, startsWith, display
Removal of longest key in a trie
Number of keys with common prefix in trie
Keys starts with and ends with in trie
Finding longest key in trie

Bit Manipulation

Reverse integer
Find if a number is power of two
Power set
Single number
Missing number
Number of bits to be flipped to convert A to B
Reverse bits
Sum of two integers

Backtracking

Palindrome partitioning
Subsets
Print all permutations of a string
N Queens
Sudoko solver
Word search
Rat in a maze
Combination sum

Dynamic programming

Coin change
0-1 Knapsack
Fibonacci number
Longest increasing subsequence
Egg dropping
Edit distance
Climbing stairs
Matrix chain multiplication

Data Structures and Algorithms (DSA) Online Courses

Data Structures and Algorithms in C/C++/C#/Java/Python (DSA) online courses.