Graph Algorithms
Run BFS, DFS, shortest path, topological sort, or cycle detection on a graph you paste in. Directed or undirected, weighted or unweighted. Runs entirely in your browser — no server, no sign-up.
What this tool does
Run a classic graph algorithm on a graph you describe yourself. Paste an edge list, choose an algorithm, and get the answer instantly — right in your browser. Nothing is uploaded to a server; it runs locally, works offline, and needs no sign-up.
How to describe your graph
Put one edge per line. The separator is flexible — all of these mean an edge
between a and b:
a -> b
a - b
a b
a,b
A line with a single label (like z) adds an isolated node. Blank lines and
lines starting with # are ignored, so you can comment your graph.
For a weighted graph, turn on Weighted and add a number at the end of the line:
a -> b : 3
a -> c 5
b -> c 1
Turn on Directed to treat each edge as one-way (a → b only). Leave it off
for an undirected graph, where every edge goes both ways.
Algorithms
| Algorithm | What it computes |
|---|---|
| BFS (breadth-first search) | Visit order exploring the graph level by level from a start node. |
| DFS (depth-first search) | Visit order exploring as deep as possible before backtracking. |
| Shortest path | The cheapest route from a start node to an end node (Dijkstra when weighted, fewest hops when not). |
| Topological sort | A linear ordering of a directed acyclic graph so every edge points forward. Requires a directed graph. |
| Cycle detection | Reports whether the graph contains a cycle, and shows an example. |
BFS, DFS, and shortest path need a Start node; shortest path also needs an End node.
Examples
| Edge list | Algorithm | Result |
|---|---|---|
a - b, a - c, b - d | BFS from a | a → b → c → d |
a - b, a - c, b - d | DFS from a | a → b → d → c |
a→b:1, a→c:5, b→c:1 (directed, weighted) | Shortest path a→c | a → b → c, distance 2 |
a→b, a→c, b→d, c→d (directed) | Topological sort | a → b → c → d |
a→b, b→c, c→a (directed) | Cycle detection | cycle found: a → b → c → a |
FAQ
Is it free and private?
Yes — your graph never leaves your device, and the tool keeps working offline once the page has loaded.
Directed or undirected?
Use Directed for one-way relationships (task dependencies, web links, follower graphs). Leave it off for symmetric relationships (roads, friendships). Topological sort only makes sense on a directed graph.
What does “weighted” do?
It tells the parser to read a trailing number on each edge as a distance/cost. Shortest path then uses Dijkstra’s algorithm. Weights must be non-negative.
Why does shortest path not take the direct edge?
Dijkstra finds the cheapest route by total weight — a longer chain of small edges can beat one expensive direct edge.
What if a node can’t be reached?
BFS/DFS report how many nodes they reached; shortest path says no path exists when the end node is unreachable from the start.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool graph-algorithms "a -> b
a -> c
b -> d"New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/graph-algorithms/?edges=a%20-%3E%20b%0Aa%20-%3E%20c%0Ab%20-%3E%20d&algorithm=bfs&directed=true&weighted=true&start=a&end=dMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.