Interviews
DSA solutions, core implementations, and interview prep material.
What's here
- 400+ solutions across LeetCode, Neetcode 150, and Striver Sheet
- 12 data structure implementations from scratch in Python
- Python tricks and language-specific interview material
- OS fundamentals with C/C++ examples
Sections
Time Complexity Cheatsheet
| Complexity |
Description |
Examples |
| O(1) |
Constant |
Hash table lookup |
| O(log n) |
Logarithmic |
Binary search |
| O(n) |
Linear |
Single loop over array |
| O(n log n) |
Linearithmic |
Merge sort, quicksort (avg) |
| O(n^2) |
Quadratic |
Nested loops, bubble sort |
| O(2^n) |
Exponential |
Recursive fibonacci |
| O(n!) |
Factorial |
Permutations, TSP |
Common Data Structure Operations
| Structure |
Access |
Search |
Insert |
Delete |
| Array |
O(1) |
O(n) |
O(n) |
O(n) |
| Hash Table |
- |
O(1) avg |
O(1) avg |
O(1) avg |
| Linked List |
O(n) |
O(n) |
O(1) head |
O(1) head |
| BST (balanced) |
O(log n) |
O(log n) |
O(log n) |
O(log n) |
| Heap |
- |
O(n) |
O(log n) |
O(log n) |