Coding-Practice
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shivaamm
Learning DSA - From 100DaysOfCode challenge to Placement Preparation:) [ C++]
DSA using C++ Language 
This repository contains all the Coding Problems solved by me on different platforms.
- Find all topic wise questions in different folders :)
- From Basic to Hard level questions under each topic
- Problems are from Leetcode and Geeksforgeeks website.
- Separate folders for CP (Codechef and Codeforces).. All Solutions are not optimised.
- Possibility that many questions repeat in same folder or under different topic.
- Multiple Solutions are given for problems (eg. Some problems can be solved using different data-strutures, so multiple solutions are there, maps, sets, brute force, optimised code, etc)
- ATTENTION!! This repository is not for Important questions.
- Press "CTRL + K" for quick find using command pallete.
Cheatsheet link - https://www.bigocheatsheet.com/
Big O Notation Complexity
Data Structures in Big O Notation
| Data Structure | Add/Insert | Remove/Delete | Access/Get | Search/Contains | Space Complexity |
|---|---|---|---|---|---|
| Array | O(n) |
O(n) |
O(1) |
O(n) |
O(n) |
| Queue | O(1) |
O(1) |
O(n) |
O(n) |
O(n) |
| Stack | O(1) |
O(1) |
O(n) |
O(n) |
O(n) |
| HashSet | O(1) |
O(1) |
- | O(1) |
O(n) |
| HashMap | O(1) |
O(1) |
O(1) |
O(1) |
O(n) |
| Singly LinkedList | O(1) |
O(1) |
O(n) |
O(n) |
O(n) |
| Doubly LinkedList | O(1) |
O(1) |
O(n) |
O(n) |
O(n) |
| Circular Singly LinkedList | O(1) |
O(1) |
O(n) |
O(n) |
O(n) |
| Circular Doubly LinkedList | O(1) |
O(1) |
O(n) |
O(n) |
O(n) |
| Binary Search Tree | O(log n) |
O(log n) |
O(log n) |
O(log n) |
O(n) |
| Binary Min Heap | O(log n) |
O(log n) |
O(1) |
O(n) |
O(n) |
| Binary Max Heap | O(log n) |
O(log n) |
O(1) |
O(n) |
O(n) |
Sorting Algorithms in Big O Notiation
| Sort Algorithm | Best | Average | Worst | Space Complexity |
|---|---|---|---|---|
| Selection Sort | O(n^2) |
O(n^2) |
O(n^2) |
O(1) |
| Insertion Sort | O(n) |
O(n^2) |
O(n^2) |
O(1) |
| Quick Sort | O(log n) |
O(log n) |
O(n^2) |
O(log n) |
| Merge Sort | O(log n) |
O(log n) |
O(log n) |
O(n) |
ERRORS
100DaysOfCode
Summary (click here):
This will be the repository for C++ topic wise questions, practice questions and DSA :)Day 1: 4 Codechef questions completed.
Day 2: Array
Day 3: OFF
Day 4: Codechef and STL Vectors intro
Day 5: Vectors
Day 6: Vectors videos and explanation.
Day 7: Break
Day 8: Practiced Coding questions problem solving
Day 9: Coding Questions practice(problem solving)
Day 10: Vectors problem
Day 11: Explored Stacks
Day 12-13: Stacks using arrays [break time] .'. Hackathon time
Day 14: BREAK!!!!!! .................Hackathon finished
Day 15: Vectors and Templates
Day 16: Linked List & Stacks Basic implementation using c++
Day 17:Linked List
Day 18: Vectors Hackerrank
Day 19: Hackerrank problems
Day 20: Vectors and linked list
Day 21: Hackerearth coding contest challenge
Day 22: Earned 5 star on hackerrank C++ badge
Day 23: Hackerrank contest and problem solving
Day 24: Vectors Practice with leetcode questions
Day 25: Leetcode questions( used vectors bool and stack and started using in functions)
Day 26: Leetcode questions (string and functions) Total 7 done
Day 27: Leetcode questions (9 done)(Remove dupliates using unique) Done 12 questions :)
Day 28: Leetcode climbing question, single number(Using XOR ques) learnt new approach [Done 15 questions]
Day 29: Leetcode 17 questions done. Finally (Done 22) completed 1.32% :)
Day 30: Leetcode 23 questions done ((((break time))))
Day 31: Stacks and Linked list understanding using stl (using stl reduces the lines of code and makes it easy to understand the code)
Day 32: Implementation of LL and stacks in Dev c++
Day 33: Theory part of linked list and stacks
END SEM BREAK
Day 34: Back to Coding!! Starting with Leetcode questions
Day 35: Stacks problem solving question on hackerearth
- Solved another tricky question on hackerearth * Stack game problem partially solved (half test cases passed)
Day 36: Solved One question of stacks on leetcode :)
Day 37: Leetcode question (Stacks topic but solved with arrays)
Day 38: Leetcode stacks easy tag questions(solved one at night)
- Codeforces solved 3 question
Day 39: Codeforces question (hulk) and leetcode stacks question
- First codechef challenge (jan 2021 challenge)
- Solved 2 contest questions
Day 40: Solved 4 questions of div3(1st contest) codechef [Long challenge]
- Tried 5th question but failed
Day 41: Codechef problems from A2oj ladder (A division problems)
- Participated in codechef challenge (solved one full question)
Day 42: Studied Stl Maps + Codeforces virtual contest
Day 43: Contest over understood the problem that couldn't solve(used dp approach and 0/1 knapsack problem approach to solve) -> Queues and implementation of queues
Day 44: Leetcode 1st medium question of Queues
- GFG practice questions
Day 45: Codechef past contest and gfg practice questions :)
Day 46: Linked List implementation and practice questions.
Day 47: Linked list practice questions and codeforces question
Day 48: Insertions and Reversal in singly linked list (C and C++)
- Solved Leetcode and gfg questions
Day 49: Linked list different platform practice questions
Day 50: Revision day (arrays, stacks, queues, linked list solved questions) [try pen paper coding]
- [x] Half done
Day 51: Stacks and Queues using linked list and revision of solved questions :)
Day 52: Notes of linked list with pen paper visualizations to under better(questions solved approaches visuals) :)
- Codechef contest (Couldn't solve any question, will read editorial)
Day 53: Linked list gfg questions and notes for future reference
- Arrays Strings gfg practice questions
Day 54: Linked list medium level questions, Time Complexity, Bit Manipulations
Day 55: Bit Manipulation Algo, Doubly Linked list(traversal, create, insertions)
Day 56: Doubly lined list (deletions and reversal)[leetcode medium reversal question is really good]
Day 57: Strings questions and linked list medium and hard level questions practice :)
BREAK DAY ** STL MAP AND SET, HASHING INTRO
Day 58: Cicular Linked list(insertions,deletions and practice) and Operating systems
- reverse and aptitude topic
Day 59: Strings leetcode questions and Linked list hard questions
Day 60: Maps, Unordered maps, hashing practice questions :)
Day 61: Codechef challenge, Maps, Leetcode question(feb)
Day 62: Trees Introduction :)
Day 63: Trees geeksforgeeks questions practice :)
Day 64: Trees leetcode and gfg questions and notes visuals for recursion :)
Day 65: TREES and LINKED LIST REVISION AND PRACTICE QUESTIONS (10 DAYS DRILL)
Range Queries Problems
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Preparation for placement begins...Stopped counting days (Done with Basics)
DS Algo Foundation GFG Course
CS Core fundamentals Aptitude Company wise Questions
July 1st Companies started coming
DATE - SAT AUG 28 PLACED (Now having 2 offers)
Applying for Off-campus opportunities Off campus resume updated -
- Done with first interview at Google for SDE role
- Another upcoming interview at Google
Onto new learnings
Welcome Year 2022
- Going to empty my current To-Do list one by one.
shivaamm