Algo Workout (Java)

A focused Java workspace for practicing data structures and algorithms for coding interviews.

Project Structure

.
├─ README.md
└─ src
   ├─ main
   │  └─ java
   │     └─ com/podopryhora/algoworkout
   │        ├─ App.java
   │        ├─ algorithms
   │        ├─ ds
   │        └─ leetcode
   └─ test
      └─ java
         └─ com/podopryhora/algoworkout

Getting Started

Run tests with the Gradle wrapper:

./gradlew test

Implementation Plan (Easiest → Hardest)

Data Structures

• Arrays (custom dynamic array)
• Singly linked list
• Doubly linked list
• Stack (array + linked list)
• Queue (array + linked list)
• Blocking queue (array + lock)
• Deque
• Hash map
• Hash table (separate chaining)
• Hash table (open addressing)
• Binary heap (min/max)
• Binary search tree
• AVL tree
• Red-black tree
• Trie
• Disjoint set (union-find)
• Graph (adjacency list/matrix)

Algorithms

• Linear search
• Binary search
• Two pointers patterns
• Sliding window
• Fixed window
• Prefix sum
• Sorting: bubble, selection, insertion
• Sorting: merge, quick, heap
• Bit manipulation basics
• Recursion patterns
• LRU cache
• Backtracking: subsets, permutations, combinations
• Token Bucket Algorithm
• Leaky Bucket Algorithm
• Greedy: interval scheduling, activity selection
• BFS / DFS
• Topological sort
• Shortest path: Dijkstra, Bellman-Ford
• Minimum spanning tree: Kruskal, Prim
• Dynamic programming: 1D (fib, house robber)
• Dynamic programming: 2D (knapsack, LCS)
• String algorithms: KMP, Rabin-Karp
• Advanced: segment tree, Fenwick tree

LeetCode problems

Easy

• Two Sum
• Palindrome Number
• Fizz Buzz
• Array Shuffle
• Max Consecutive Ones
• Valid Palindrome
• Best Time to Buy and Sell Stock

Medium

• Longest Palindromic Substring
• Add Two Numbers
• Three Sum
• Longest Substring Without Repeating Characters
• Best Time to Buy and Sell Stock II

Hard

• Best Time to Buy and Sell Stock III
• Best Time to Buy and Sell Stock IV
• Best Time to Buy and Sell Stock with Cooldown

Example

• LinearSearch lives in src/main/java/com/podopryhora/algoworkout/algorithms/search/LinearSearch.java
• Tests live in src/test/java/com/podopryhora/algoworkout/algorithms/search/LinearSearchTest.java