A dead end is a passage in a maze that terminates with no way forward — your only option is to turn around and retrace your steps. Dead ends are the most recognizable feature of any maze. They're what make you groan "wrong turn!" The ratio of dead ends to junctions, combined with their average length, defines much of a maze's complexity and character.
Technically, a dead-end cell has exactly one connection to the rest of the maze. In graph terms, it's a "leaf node" — a cell with degree 1. You can enter it but must leave the same way.
A dead end isn't always a single cell. It's the entire corridor from the termination point back to the last junction. A long dead end (20+ cells) wastes significant time; a short one (1-2 cells) is barely noticeable.
The percentage of total cells that are part of dead-end branches. In a typical recursive backtracking maze, about 25-30% of cells are in dead ends. In a Prim's maze, it can reach 40-50% but each dead end is much shorter.
Every dead end costs you 2× its length in wasted steps — once to walk in, once to walk back out. This is why dead-end length is the strongest factor in perceived maze difficulty.
Dead ends are the emotional core of maze solving. A long dead end that looked promising is frustrating. A short one you can quickly recover from is barely a setback. Game designers carefully tune dead-end length to balance challenge with enjoyment — too many long dead ends make a maze feel unfair.
The classic strategy is "wall following" (keep one hand on the wall), which systematically explores all dead ends. The smarter approach is to mark junctions and dead ends as "explored" — this is essentially what DFS does. For optimal solving, BFS avoids dead ends entirely by expanding evenly.
| Algorithm | Dead-End Count | Average Length | Total Penalty |
|---|---|---|---|
| Recursive Backtracking | Few | Long | High ⚠️ |
| Prim's | Many | Short | Medium |
| Kruskal's | Moderate | Moderate | Medium |
| Wilson's | Uniform | Uniform | High ⚠️ |
Every maze on HTML Maze has dead ends waiting to test your strategy. Can you spot them early and avoid backtracking?
Dead ends are the primary penalty for wrong turns. More dead ends = more chances to go wrong. Longer dead ends = more time wasted per mistake. The product of count × length is the strongest predictor of how hard a maze feels.
Prim's creates the most by count, but they're short. Recursive backtracking creates fewer, but they're much longer and more punishing.
Use the "wall follower" rule (keep one hand on the wall) for systematic coverage. For a smarter approach, mark junctions and avoid re-entering passages you've already explored — this is essentially DFS with visited tracking.