## A Step by Step Guide for Placement Preparation all IT companies

On-Campus placement, Off placement Checklist procedure

The key to crack the campus placements, Placement Preparation Strategy for Product, Service, and Analytics-Based Companies.

# Data Structures:

1. Array
1. N/2, N/3 greatest Number
1. Merge overlapping intervals
1. Rotate matrix
1. String
1. Pattern matching algorithms (KMP + Rabin Karp)
1. Using StringBuilder class -> Add, Multiply Strings

https://www.geeksforgeeks.org/stringbuilder-class-in-java-with-examples/

1. String compression algorithm

1. Detect cycle in a linkedlist – Floyd Algo
1. Reverse a linked list + reverse in groups
1. Stack
1. Implementation of Stack

https://www.geeksforgeeks.org/stack-data-structure-introduction-program/

1. Balance parenthesis

https://leetcode.com/problems/valid-parentheses/

1. Trapping rain water
1. Implement min stack

1. Queue
1. Implementation of Queue + Deque

https://www.geeksforgeeks.org/queue-set-1introduction-and-array-implementation/

https://www.geeksforgeeks.org/implementation-deque-using-circular-array/

https://www.geeksforgeeks.org/deque-interface-java-example/

1. Sliding window maximum
1. Implement BFS
1. Implement Level order in Binary tree

1. PriorityQueue or Heap
1. Implementation of Heap Data structure
1. Connect n ropes with min cost: https://www.geeksforgeeks.org/connect-n-ropes-minimum-cost/
2. Median of running stream: https://www.geeksforgeeks.org/median-of-stream-of-running-integers-using-stl/
3. LRU and LFU cache

1. Set & Map
1. Internal working of HashMap
1. 4-sum
1. Longest substring without repeat: https://www.interviewbit.com/problems/longest-substring-without-repeat/
1. Binary Tree
1. Implementation: insert, delete, traverse: https://youtu.be/wYT3hsc1XMs
2. Print top view, left view, right view, bottom view, level order, zig-zag traversal of Binary tree

https://www.geeksforgeeks.org/level-order-tree-traversal/

1. Invert a binary tree: https://leetcode.com/problems/invert-binary-tree/
2. Lowest common ancestor

1. Binary Search Tree
1. Implementation

1. Check if a tree is BST or not
1. AVL tree and rotation

1. Graph
1. Implementation, BFS and DFS traversals
1. Topological sorting
1. Bellman ford Algorithm
1. Dijkstra’s Algorithm
1. Prim’s Algorithm
1. Kruskal’s Algorithm
1. Unique Islands Problem: https://www.geeksforgeeks.org/find-the-number-of-distinct-islands-in-a-2d-matrix/

1. Trie
1. Implementation
1. Segment Trees : More important in CP
1. Implementation

# Algorithms:

1. Two pointers Algorithm
1. 3-Sum
1. Container with most water
1. Sort the array containing only 0, 1 and 2
1. Math
2. Euclid GCD: https://www.geeksforgeeks.org/euclidean-algorithms-basic-and-extended/
3. Sieve of Eratosthenes:
1. Recursion + Backtracking
1. Sudoku solver
1. N-Queens Problem
1. Permutation and Combinations (Bruteforce)
1. Bits Manipulation + Mathematics
1. Find one  non-repeating number, find two
1. Count 1 bits in a number
1. Divide & Conquer
1. Merge Sort
1. Median of two sorted arrays

1. Binary Searching
1. Find upper and lower bound using Binary search
1. Allocate books: https://www.interviewbit.com/problems/allocate-books/
1. Greedy Programming
1. Candy distribution: https://www.interviewbit.com/problems/distribute-candy/
2. Gas station: https://www.interviewbit.com/problems/gas-station/
3. Fractional Knapsack
1. Dynamic Programming
1. 0/1 Knapsack:https://youtu.be/xCbYmUPvc2Q
2. Longest increasing subsequence
1. Matrix chain multiplication
1. Coin change problem

# Operating System:

2. Process scheduling algorithms
3. Critical section Problem
5. Memory management
1. Paging
2. Segmentation
6. Page replacement algorithms
7. Disk scheduling algorithms

# DBMS:

1. Types of Keys: Candidate, Super, Foriengn keys
2. Normal Forms
3. Joins
4. SQL queries
5. ACID properties
6. Indexing: B trees, B+ trees concepts

# System design:

1. Low-level design
1. Class, ER diagrams
2. OOPS concepts
3. Design Elevator system, Parking Lot, MakeMyTrip System
2. High-level design
1. Scaling
2. Distributed systems
3. Microservice and Monolithic architecture