Pattern Almanac

Master 144 algorithm patterns to ace your coding interviews

144 patterns

1D DP

Dynamic Programming

2D DP

Array / Design

Backtracking

Backtracking (Permutations)

Backtracking / Skip Duplicates

Backtracking / Stack

Backtracking on Grid

Backtracking with Constraints

Backtracking with Duplicate Handling

Backtracking with Reuse

Backtracking with Skip Duplicates

Backtracking with Validation

BFS

BFS / Queue

BFS or Bellman-Ford

BFS or DFS with Level Tracking

Binary Exponentiation

Binary Search

Binary Search (Modified)

Binary Search / Matrix

Binary Search / Modified

Binary Search + BFS or Dijkstra

Binary Search on Answer

Binary Search with HashMap

Bit Manipulation

Bit Manipulation (XOR)

Boyer-Moore Voting / Hash Map

BST Properties

DFS / BFS

DFS / Combinatorics

DFS with Memoization

2-D Dynamic Programming

DFS/BFS (Reverse)

DFS/BFS + Cycle Detection

DFS/BFS from Border

DFS/BFS or Union Find

DFS/BFS with Hash Map

Dijkstra's Algorithm

Divide and Conquer / BST

DP / LIS

Dynamic Programming (0/1 Knapsack)

1-D Dynamic Programming

Dynamic Programming (1D)

1-D Dynamic Programming

Dynamic Programming (1D) with Cases

1-D Dynamic Programming

Dynamic Programming (2D)

2-D Dynamic Programming

Dynamic Programming (Interval DP)

2-D Dynamic Programming

Dynamic Programming (LIS)

1-D Dynamic Programming

Dynamic Programming (State Machine)

2-D Dynamic Programming

Dynamic Programming (Subset Sum)

2-D Dynamic Programming

Dynamic Programming (Track Min/Max)

1-D Dynamic Programming

Dynamic Programming (Unbounded Knapsack)

1-D Dynamic Programming

Dynamic Programming + Bit Manipulation

Eulerian Path (Hierholzer's)

Expand Around Center

1-D Dynamic Programming

Fast & Slow Pointers (Floyd's)

Floyd's Cycle Detection

Greedy

Greedy (BFS-like)

Greedy / DP

Greedy / Intervals

Greedy with Hash Map

Greedy with Range

Hash Map

Hash Map / Design

Hash Map / Frequency Counter

Hash Map / Two Pointers

Hash Map + Doubly Linked List

Hash Map + Heap (K-way merge)

Heap / Priority Queue

Hash Map or Interweaving

Hash Map with Sorted Key

Hash Set

Hash Set (multiple)

Hash Set or Fast/Slow Pointers

Heap / Bucket Sort

Heap / Priority Queue

Heap / Sweep Line

Heap with Cooldown Queue

Heap / Priority Queue

In-order Traversal

Intervals

Intervals / Sorting

Kadane's Algorithm

Linked List

Linked List / Two Pointers

Linked List Arithmetic

Linked List Reversal

Linked List Reversal in Groups

Math

Math / Probability

Math / Simulation

Math / XOR / Hash Set

Math or XOR

Matrix Manipulation

Matrix Traversal

Max Heap

Heap / Priority Queue

Min Heap of Size K

Heap / Priority Queue

Min Heap or Quick Select

Heap / Priority Queue

Monotonic Deque

Monotonic Stack

Multi-source BFS

Multiple Steps (Find mid, Reverse, Merge)

Prefix/Suffix Product

Prim's or Kruskal's MST

Quick Select or Min Heap

Heap / Priority Queue

Shell Scripting

Simulation

Sliding Window

Sliding Window / Greedy

Sliding Window with Frequency Match

Sorting + Heap

Stack

Stack / Design

Stack / Linked List

Stack / Monotonic Stack

Stack with Min Tracking

String

String / Simulation

String Manipulation / Delimiter

Topological Sort

Topological Sort / Cycle Detection

Tree DFS

Tree DFS (Nested)

Tree DFS / BFS

Tree DFS / In-order

Tree DFS / Prefix Sum

Tree DFS / Recursion

Tree DFS with Global Max

Tree DFS with Global Variable

Tree DFS with Height Tracking

Tree DFS with Max Tracking

Tree DFS with Range

Tree DFS/BFS with Encoding

Tree Reconstruction

Trie / DP

Trie + Backtracking

Trie Data Structure

Trie with DFS

Two Heaps

Heap / Priority Queue

Two Pointers

Two Pointers (Gap)

Two Pointers (Greedy)

Two Pointers / Linked List

Two Pointers / Merge

Two Pointers / Sliding Window

Two Pointers with Sorting

Union Find

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