Competitive Programming Tools

Free competitive programming tools — graph visualizer, segment tree builder, bitmask planner, Big-O complexity analyzer and interval merger.

31 tools

Code Formatter

Format and beautify C++, Java, and Python code with consistent indentation. 100% client-side — no code leaves your browser.

Matrix Generator

Generate grid/matrix inputs for competitive programming. Random, zeros, identity, or sequential fill. Outputs in multiple formats.

Complexity Calc

Estimate Big-O operations and runtime for any N. Interactive reference table for all complexity classes from O(1) to O(N!).

Bit Visualizer

Toggle 32/64-bit grids. Click bits to flip them live and see decimal recalculate. Shows popcountll, clzll, ctzll, and MSB instantly.

Bitmask Planner

Input set size N (≤12). Visualize all 2^N bitmasks, submask iterations, and generate ready-to-paste C++ DP skeleton.

Prime Factors

Input N to instantly view prime factorization, total divisors, Euler totient, and full sorted divisors list with prime highlighting.

MEX Calc

Input a comma-separated array and see the MEX (Minimum Excluded) computed step-by-step with frequency table and visual walkthrough.

Interval Merger

Input pairs of ranges like [1,4],[3,7]. Visualizes overlaps on a timeline and collapses them into merged segments instantly.

Matrix Rotation

Input a 2D matrix, choose 90°/180°/270° CW or CCW rotation. See the visual index shift and get the C++ implementation.

PBDS Generator

Generate ready-to-paste C++ Order Statistics Tree code. Configure key type, comparator, and duplicate support. One-click copy.

Segment Tree

Input an array, choose sum/min/max/gcd. See the segment tree visualization and get a complete C++ class template to copy.

Graph Visualizer

Paste CP-style edge lists and watch a force-directed graph build itself. Drag nodes, toggle directed and 0/1-indexed, then copy the adjacency list.

Stress Tester

Paste your brute force, optimal solution and test generator to get a downloadable Python or Bash stress-test script that finds counter-examples.

Modulo Calc

Compute modular inverse, fast power modulo, and nCr mod p using BigInt precision. One-click C++ snippet output for each operation.

Convex Hull

Click the canvas to place coordinate points. Renders the enclosing convex hull polygon live using Andrew's monotone chain. Outputs C++ points vector.

Path Finder

Paint walls on an N×M grid, set start and end cells, then run BFS to visualize the shortest path. Copy the grid as a C++ 2D vector instantly.

Offline Judge

Run your JavaScript solution against unlimited custom test cases in a sandboxed Web Worker. Get AC/WA/TLE/RE verdicts and per-case run times.

Big-O Analyzer

Benchmark your algorithm across doubling input sizes to measure its real time complexity, fit O(1) to O(2ⁿ), and predict whether it will TLE.

Combinatorics

Calculate nCr, nPr, factorials, Catalan numbers and Stirling numbers using exact BigInt arithmetic. Step-by-step working shown for every result.

DP Table Builder

Animate DP table fills for Fibonacci, LCS, 0-1 Knapsack, Coin Change and Edit Distance. Heat-map coloring, TSV copy, and custom blank tables.

Extended GCD

Compute GCD, LCM, and Bezout coefficients x, y for ax+by=gcd with a full Euclidean step trace and modular inverse — BigInt-exact up to 10¹⁸.

Sieve Visualizer

Animate the Sieve of Eratosthenes step by step on a colour-coded grid. Enter any limit up to 500, step through each elimination, and copy the prime list.

Binary Search

Step through binary search on your own sorted array. Highlights lo, hi and mid at each probe. Play, pause or step manually. O(log n) worst-case shown.

Sorting Visualizer

Watch bubble, selection, insertion, merge, quick and heap sort run one comparison at a time, with step controls and live comparison and write counts.

Sparse Table RMQ

Build a sparse table for O(1) range minimum queries. Visualise every level of the 2D precomputation table, run live queries, and copy the C++ template.

Union-Find DSU

Union-Find (DSU) visualizer: path compression, union by rank, live forest view, parent/rank/size arrays and C++ template. Step-through or manual mode.

Also in Competitive Programming

Tools from other categories tagged with Competitive Programming

Text Diff

Compare two blocks of text side-by-side. Highlights added, removed, and unchanged lines with a visual diff view.

Palindrome

Check if any word, phrase, or sentence is a palindrome. Ignore spaces, punctuation, and case. Shows character mirror diff and longest palindromic substring.

Text Separator

Join lines into a delimited string or split delimited text into separate lines. Comma, pipe, tab, semicolon, space, or any custom delimiter.

ASCII Table

Look up any of the 256 ASCII and Latin-1 characters by decimal, hex, octal, or binary, with full names, control abbreviations, and one-click copy.

Prime Checker

Check whether any positive integer is prime, with the full prime factorisation when it is not. Trial division to ⌈√n⌉ — deterministic and exact.

Why These Tools

This corner of the site came straight out of contest practice. Bitmask & Subset DP Planner writes the C++ enumeration skeleton so the submask loop stops getting mistyped at two in the morning, and Segment Tree Blueprint does the same for build, query and update. Graph Visualizer & Editor accepts adjacency lists in the shape judges actually hand you, so there is no reformatting step between reading a problem and seeing it drawn. Binary Search Step Visualizer joins them now: paste any sorted array and a target, then step through every probe watching lo, hi and mid update — the not-found path is worth running at least once, since that is where most off-by-one bugs hide. Big-O Analyzer, prime factor trees and stress-test harnesses fill in the rest.