Competitive Programming Playground

Interactive algorithm visualizations for competitive programming problems.

BFS Order

Visualize BFS traversal order on a 2D grid starting from (0,0).

Find the minimal rotation of a circular string in O(n) time.

Divide circular array into minimal segments with bounded sum using prefix sums and binary search.

Classify points as left, right, or on a directed line segment using cross products.

Find the outermost layer of points forming a convex polygon using Andrew's monotone chain.

Classify a query point as inside, outside, or on the boundary of a polygon using ray casting.

Count interior and boundary lattice points of a polygon using Pick's theorem.

Count subordinates for each employee in a company hierarchy using DFS subtree sizes.

Check if party guests can be split into two groups with no enemies in the same group (bipartite graph).

Detect cycles in an undirected graph using DFS with 3-color marking.

Find the longest path (diameter) in a tree using double BFS.

Compute minimum edit distance between two strings using Levenshtein DP.

Find minimum production time using binary search on machine scheduling.

Split array into k groups minimizing maximum sum via binary search + greedy.

Count grid paths avoiding traps with DP (mod 10^9+7).

Answer distance queries on a tree structure using BFS depth + LCA.

Maximize movies watched by k members using greedy interval scheduling.

Count trees in rectangular areas using 2D prefix sums.

Find second minimum spanning tree cost via Kruskal + edge enumeration.

Track connected components and max size after each edge addition (DSU).

Find minimum fairies to light all mountain valleys using line-of-sight geometry.

Lights Out puzzle — toggle switches to turn all lamps on with minimum clicks.