Master fundamental and advanced algorithms essential for technical interviews at top companies. This category covers sorting algorithms, search algorithms, graph algorithms, and optimization techniques that form the foundation of computer science problem-solving.
What You’ll Learn:
Sorting algorithms: Quick sort, merge sort, heap sort
Search techniques: Binary search and variations
Graph algorithms: DFS, BFS, Dijkstra’s, topological sort
Optimization: Dynamic programming, greedy algorithms
Time and space complexity analysis
Difficulty Progression: Start with basic sorting and searching, then progress to graph algorithms and dynamic programming.
Interview Frequency: Extremely high – algorithms appear in 80%+ of technical interviews at Google, Amazon, Facebook, Microsoft, and Apple.
5 min read Why Interval Problems Matter in Interviews Interval problems appear in scheduling, calendar, and range queries — and in coding interviews […] Read article
6 min read Why String Algorithms Matter in Interviews String problems are ubiquitous in technical interviews at Google, Meta, Amazon, and Microsoft. Key Read article
6 min read Why Graph Algorithms Matter in Interviews Graph problems appear constantly in technical interviews because they model real systems: social networks Read article
6 min read The Two Heaps Pattern Two heaps maintain the lower and upper halves of a data stream, allowing O(1) access to Read article
7 min read Grid Traversal Fundamentals Most matrix problems involve: (1) BFS from one or multiple source cells, (2) DFS to explore connected Read article
6 min read When to Use an Ordered Map (Sorted Dict / TreeMap) An ordered map maintains keys in sorted order with O(log Read article
6 min read Why String Hashing? Naive string comparison is O(L) per comparison where L is the string length. String hashing converts a Read article
6 min read When to Use Two Pointers Two pointers reduce O(n²) brute force to O(n) or O(n log n) by exploiting sorted Read article
6 min read Essential Bit Operations x & y # AND: both bits must be 1 x | y # OR: at least Read article
6 min read What is Topological Sort? A topological ordering of a directed acyclic graph (DAG) is a linear ordering of vertices such Read article
6 min read Core Idea A stack (LIFO) is the right tool when the most recently seen element determines the action for the Read article
6 min read The Pattern Divide and conquer splits a problem into independent subproblems, solves each recursively, and combines the results. Three steps: Read article
6 min read GCD and LCM Euclidean algorithm: gcd(a,b) = gcd(b, a%b), base case gcd(a,0) = a. Time O(log min(a,b)). LCM: lcm(a,b) = Read article
5 min read Core Idea Build a prefix array where prefix[i] = arr[0] + arr[1] + … + arr[i-1]. Then any range sum Read article
7 min read Design patterns appear in coding interviews in two ways: the interviewer asks you to implement a specific pattern, or you’re Read article
