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DSA

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14 Topics

Every problem tagged, every concept linked. Find exactly what you need.

Number theory, combinatorics, geometry, probability

9,632·31 platforms

Dynamic Programming

Knapsack, LIS, LCS, tree DP, digit DP, DP on graphs

4,313·30 platforms

Classic BS, BS on answer, ternary search, bitonic arrays

3,709·26 platforms

KMP, Z-algo, suffix array, palindrome, pattern matching, LCS

3,426·36 platforms

Bit Manipulation

XOR tricks, bitmask DP, subsets, bit hacks, gray code

2,868·28 platforms

Binary tree, BST, traversal, LCA, diameter, n-ary trees

2,714·25 platforms

BFS, DFS, Dijkstra, MST, topological sort, SCC, flow

1,290·24 platforms

Singly/doubly LL, cycle detection, merge, reverse, sort

1,135·20 platforms

Fenwick/BIT, segment tree, sqrt decomp, Mo's algo, treap

924·24 platforms

Fixed/variable size windows, two pointers, deque optimization

610·37 platforms

Heap / Priority Queue

Min/max heap, top K, median, merge K sorted, Huffman

496·29 platforms

Matrix traversal, rotation, spiral, 2D arrays, grid geometry

331·14 platforms

Permutations, combinations, subsets, N-queens, constraint SAT

325·18 platforms

Prefix tree, dictionary, auto-complete, XOR max pair

158·17 platforms

Table of Contents

01Points & Lines2

02Triangles & Area8

03Circles & Arcs14

04Polygons22

05Convex Hull30

06Line Intersection40

07Coord. Geometry48

08Transformations56

Table of Contents

01Points & Lines2

02Triangles & Area8

03Circles & Arcs14

04Polygons22

05Convex Hull30

06Line Intersection40

07Coord. Geometry48

08Transformations56

Chapter 04

Polygons

A polygon is a plane figure bounded by straight edges. Its signed area is computed with the Shoelace formula:

A = ½|Σ(xᵢyᵢ₊₁ − xᵢ₊₁yᵢ)|

Shoelace / Gauss Area Formula

Works for any simple polygon, convex or concave.

64 problems · Difficulty: Easy-Hard

Chapter 01

Points, Lines & Distances

Two points in a plane define a unique segment. The straight-line distance between A(x₁,y₁) and B(x₂,y₂):

d = √(Δx² + Δy²)

Euclidean Distance

Manhattan Distance

d = |x₂−x₁| + |y₂−y₁|

L¹ / Taxicab Metric

142 problems · Difficulty: Easy-Medium

◆ THE SHAPE CODEX · Vol. I

Geometry
& Shapes

From the distance formula to convex hull - master every geometric structure with visual explanations, worked formulas, and 1,200+ curated DSA problems.

Chapters

01Points & Lines142 problems

02Triangles & Area98 problems

03Circles & Arcs87 problems

04Polygons & Shoelace64 problems

05Convex Hull52 problems

06Line Intersection48 problems

07Coordinate Geometry38 problems

08Geometric Transformations44 problems

09DSA Applications120 problems

1,200+

Problems

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Chapters

340

Formulas

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What You Can Do

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38,000+ problems across 50+ platforms. Filter by difficulty, platform, topic, and rating range.

Learn Patterns

194 chapters of pattern-based learning. Brute force first, then the insight, then optimal.

Curated Collections

14 core topics: DP, Graphs, Trees, Binary Search, Sliding Window, and more. Practice systematically.

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29,968+ problems. 194 chapters. One platform.

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