Graphs Visualizers

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Step through every Graphs problem with animated runtime state, source highlighting, and curated test cases. Built for coding-interview prep and durable algorithmic intuition.

Alien Dictionary

Derive character order from an alien dictionary using Topological Sort (Kahn's Algorithm).

Topological Sort

All Paths From Source to Target

Use backtracking through a Directed Acyclic Graph (DAG) to eagerly collect every unique path to the target.

Graph Backtracking DFS

Bellman Ford Algorithm

Computes the absolute shortest paths sequentially from a source node to all other reachable nodes. Safely handles negative edges and detects negative cycles.

Graphs / Shortest Path

Breadth First Search (BFS)

Generic Level-Order Graph Traversal starting from a given node. Essential foundation for shortest path algorithms.

Graphs / Traversal

Cheapest Flights Within K Stops

Apply a level-bounded Bellman-Ford traversal to find the minimum cost trail with at most K transfers.

Bellman-Ford / BFS

Perform a BFS to deeply copy an undirected graph, resolving cycles using a hash map.

Graph BFS / DFS

Course Schedule

Detect cycles in a directed graph using DFS (visited states) to determine if all courses can be finished.

DFS Cycle Detection

Course Schedule II

Determine the topological order of courses using Kahn's Algorithm (BFS) and detect cycles in prerequisites.

Topological Sort (Kahn's)

Depth First Search (DFS)

Generic Graph Traversal that dives deep into branches before backtracking. Foundational for cycle detection and topological sort.

Graphs / Traversal

Detect Cycle in Undirected Graph

Use DFS to check for cycles. We find a cycle when we explore a node that is already visited and is not the direct parent of the current node.

Dijkstra's Algorithm

Computes the absolute shortest paths sequentially from a source node to all other reachable nodes in a positively edge-weighted graph.

Graphs / Shortest Path

Find if Path Exists in Graph

Convert an edge list to an adjacency list, then run BFS with visited sets until the destination is found.

Find the City with Smallest Neighbors

Execute Floyd-Warshall to compute all-pairs shortest paths and identify the city with minimal threshold-connectivity.

Floyd-Warshall (All-Pairs)

Floyd Warshall Algorithm

Computes the shortest paths between ALL pairs of nodes simultaneously in a weighted graph using a 2D matrix dynamic programming approach.

Graphs / Shortest Path

Graph Valid Tree

Verify if a graph is a valid tree (connected and no cycles) using Union-Find.

Kahn's Algorithm (BFS Topo Sort)

Computes a Topological Sort of a DAG using BFS by systematically removing nodes with 0 incoming edges. Unreachable nodes indicate a cycle.

Graphs / Topo Sort

Kruskal's Algorithm (MST)

Constructs a Minimum Spanning Tree greedily by sorting edges by weight and using a Disjoint Set structure to safely combine components.

Graphs / Minimum Spanning Tree

Max Area of Island

Scan a grid and launch recursive DFS traversals to sink sub-islands and measure their cumulative area.

Graph Matrix DFS

Min Cost to Connect All Points

Construct a Minimum Spanning Tree (MST) using Prim's algorithm to link 2D points with minimal total Manhattan distance.

Network Delay Time

Broadcast a signal through a weighted directed graph using Dijkstra's Algorithm to find total transmission time.

Dijkstra's Algorithm

Number of Islands

Identify and count disconnected land masses in a grid using recursive DFS flood filling.

Graph Matrix DFS

Number of Operations to Make Network Connected

Count isolated network clusters using DSU and determine the minimum number of cables needed to bridge them.

Union Find (DSU)

Number of Ways to Arrive at Destination

Extend Dijkstra's algorithm to count the total number of distinct paths that achieve the absolute minimum travel time.

Pacific Atlantic Water Flow

Multi-source DFS/BFS to find cells that can reach both the Pacific and Atlantic oceans.

Graph Matrix DFS

Prim's Algorithm (MST)

Constructs a Minimum Spanning Tree greedily by growing a single connected component and selecting the cheapest incident edge at each step.

Graphs / Minimum Spanning Tree

Reconstruct Itinerary

Reconstruct a flight itinerary using Hierholzer's algorithm for finding an Eulerian Path.

Hierholzer Algorithm

Redundant Connection

Use a Disjoint Set Union (DSU) structure to identify exactly which edge mathematically creates a cycle in a tree structure.

Union Find (DSU)

Shortest Path in Binary Matrix

Navigate an 8-directional binary grid using BFS to find the minimal distance from start to finish.

Shortest Path in Unweighted Graph - BFS

Finds the shortest path from a source node to all other nodes in an unweighted graph using Level Order Traversal (BFS).

Graphs / Shortest Path

Swim in Rising Water

Find the minimum time to swim to the target using Dijkstra on a grid of elevations.

Dijkstra Priority Queue

Topological Sort - DFS

Orders a Directed Acyclic Graph (DAG) linearly such that for every directed edge U -> V, node U comes before V. DFS solves this natively using a post-order stack process.

Graphs / Topo Sort

Find the shortest transformation sequence between two words using BFS on word mutations.

BFS Shortest Path