30 Days Interview Preparation Plan🎯 Day1: (Arrays) Sort an array of 0’s 1’s 2’s without using extra space or sorting Algo Repeat and Missing Number Merge two sorted Arrays without extra space Kadane’s Algorithm Merge Overlapping Subintervals Find the duplicate in an array of N+1 integers. Day2: (Arrays) Set Matrix Zeros Pascal Triangle Next Permutation Inversion of Array (Using Merge Sort) Stock Buy and Sell Rotate Matrix Day3: (Arrays/maths) Search in a 2D matrix Pow(X,n) Majority Element (>N/2 times) Majority Element (>N/3 times) Grid Unique Paths Reverse Pairs (Leetcode) Go through Puzzles from GFG (Search on your own) Day4: (Hashing) 2 Sum problem 4 Sum problem Longest Consecutive Sequence Largest Subarray with 0 sum Count the number of subarrays with the given XOR (this clears a lot of problems) Longest substring without repeat Day5: (LinkedList) Reverse a LinkedList Find the middle of LinkedList Merge two sorted Linked List Remove the N-th node from the back of LinkedList Delete a given Node when a node is given. (0(1) solution) Add two numbers as LinkedList Day6: Find the intersection point of Y LinkedList Detect a cycle in Linked List Reverse a LinkedList in groups of size k Check if a LinkedList is a palindrome or not. Find the starting point of the Loop of LinkedList Flattening of a LinkedList Rotate a LinkedList Day7: (2-pointer) Clone a Linked List with random and next pointer 3 sum Trapping rainwater Remove Duplicate from the Sorted array Max consecutive ones Day8: (Greedy) N meeting in one room Minimum number of platforms required for a railway Job sequencing Problem Fractional Knapsack Problem Greedy algorithm to find the minimum number of coins Activity Selection (it is the same as N meeting in one room) Day9 (Recursion): Subset Sums Subset-II Combination sum- Combination sum Palindrome Partitioning K-th permutation Sequence Day10: (Recursion and Backtracking) Print all Permutations of a string/array N queens Problem SudokuSolver M Coloring Problem Rat in a Maze Word Break -> print all ways Day11 : (Binary Search) The N-th root of an integer (use binary search) (square root, cube root, ..) Matrix Median Find the element that appears once in the sorted array, and the rest element appears twice (Binary search) Search element in a sorted and rotated array/ find pivot where it is rotated Median of 2 sorted arrays K-th element of two sorted arrays Allocate a Minimum Number of Pages Aggressive Cows Day12: (Bits) (Optional, very rare topic in interviews, but if you have time left, someone might ask) Check if a number if a power of 2 or not in O(1) Count total set bits Divide Integers without / operator Power Set (this is very important) Find MSB in o(1) Find the square of a number without using multiplication or division operators. Day13: (Stack and Queue) Implement Stack Using Arrays Implement Queue Using Arrays Implement Stack using Queue (using single queue) Implement Queue using Stack (0(1) amortized method) Check for balanced parentheses Next Greater Element Sort a Stack Day14: Next Smaller Element LRU cache (vvvv. imp) LFU Cache (Hard, can be ignored) Largest rectangle in a histogram (Do the one-pass solution) Sliding Window Maximum Implement Min Stack Rotten Orange (Using BFS) Stock Span Problem Find the maximum or minimum of every window size The Celebrity Problem Day15: (String) Reverse Words in a String Longest Palindrome in a string Roman Number to Integer and vice versa Implement ATOI/STRSTR Longest Common Prefix Rabin Karp Day16: (String) Prefix Function/Z-Function KMP Algo / LPS(pi) array Minimum characters needed to be inserted in the beginning to make it palindromic. Check for Anagrams Count and Say Compare version numbers Day17: (Binary Tree) In-order Traversal (with recursion and without recursion) Pre-order Traversal (with recursion and without recursion) Post-order Traversal (with recursion and without recursion) Left View Of Binary Tree Bottom View of Binary Tree Top View of Binary Tree Day18: (Binary Tree) Level order Traversal / Level order traversal in spiral form Height of a Binary Tree Diameter of Binary Tree Check if the Binary tree is height-balanced or not LCA in Binary Tree Check if the two trees are identical or not Day 19: (Binary Tree) Maximum path sum Construct Binary Tree from inorder and preorder Construct Binary Tree from Inorder and Postorder Symmetric Binary Tree Flatten Binary Tree to LinkedList Check if Binary Tree is the mirror of itself or not Day 20: (Binary Search Tree) Populate Next Right pointers of the Tree Search the given Key in BST Construct BST from the given keys. Check if a BT is BST or not Find the LCA of two nodes in BST Find the in-order predecessor/successor of a given Key in BST. Day21: (BinarySearchTree) Floor and Ceil in a BST Find K-th smallest and K-th largest element in BST (2 different Questions) Find a pair with a given sum in BST BST iterator Size of the largest BST in a Binary Tree Serialize and deserialize Binary Tree Day22: (Mixed Questions) Binary Tree to Double Linked List Find the median in a stream of running integers. K-th largest element in a stream. Distinct numbers in the Window. K-th largest element in an unsorted array. Flood-fill Algorithm Day23: (Graph) Clone a graph (Not as easy as it looks) DFS BFS Detect A cycle in Undirected Graph/Directed Graph Topo Sort Number of islands (Do in Grid and Graph both) Bipartite Check Day24: (Graph) SCC(using KosaRaju’s Algo) Dijkstra's algorithm Bellman-Ford Algo Floyd Warshall Algorithm MST using Prim’s Algo MST using Kruskal’s Algo Day25: (Dynamic Programming) Max Product Subarray Longest Increasing Subsequence Longest Common Subsequence 0-1 Knapsack Edit Distance Maximum sum increasing subsequence Matrix Chain Multiplication Day26: (DP) Maximum sum path in the matrix, (count paths and similar types do, also backtrack to find the maximum path) Coin change Subset Sum Rod Cutting Egg Dropping Word Break Palindrome Partitioning (MCM Variation) Maximum profit in Job scheduling For core revision</> Day27: Revise OS notes that you would have made during your sem If not made notes, spend 2 or 3 days and make notes from Knowledge Gate. Day28: Revise DBMS notes that you would have made during your semesters. If not made notes, spend 2 or 3 days and make notes from Knowledge Gate. Day29: Revise CN notes, that you would have made during your sem. If not made notes, spend 2 or 3 days and make notes from Knowledge Gate. Day30: Make a note of how you will represent your projects, and prepare all questions related to tech which you have used in your projects. Prepare a note that you can say for 3-10 minutes when he asks you that say something about the project. Data Structures & Algorithms for Coding Interview Repository Link: https://github.com/SamirPaul1/DSAlgo In this repository, I have stored solutions to various problems and concepts of in Python3 in a structured manner.✨ Data Structures and Algorithms ✅ : Topics Covered Dynamic Programming Sorting Algorithms LinkedList Object-Oriented Programming Binary Trees Graph Algorithms Heap Matrix Trie Binary Search Backtracking Stack Queue Greedy String Bit Manipulation Array HashMap DFS BFS Two Pointers Math Recursion In various folders of the above topics, you can find questions and concepts related to that topic. For learning Dynamic Programming, we need to relate the concepts learned in one question to apply to another problem💡. In the Dynamic Programming section, you can find all the questions covered and not covered in folder-wise with my .✍️ Aditya Verma's dynamic programming playlist handwritten notes If you are preparing for an interview from then the will be helpful to you. Here I have stored solutions to questions of each day with short notes to each solution, as short notes about the approach are very helpful during revision.🎯 Striver’s SDE Sheet 30-Days-SDE-Sheet-Practice In the directory, you can find questions asked by top product-based companies. Questions-Sheet There is a collection of books and pdfs on various important computer science fundamentals in the directory.📚 BOOKS-and-PDFs View this repository in an online VSCode-like interface▶️ https://samirpaul.in/DSAlgo 🚀 I am continuously trying to improve this repository by adding new questions and concepts related to the respective topic. Please feel free to contribute to this repository.💻 If you appreciate my work, please give a star(🌟) to this repository. It motivates me. ❤️🚀
