Cross 153 miles in the fewest fill-ups — a full tank goes 24 miles.

You start with a full tank. Each station you stop at refills you back to 24 miles of range. Pick the stations so you never run dry before the finish — using as few as possible.

Practice — no rating pressure. Get as close to the optimum as you can; each play teaches the pattern.

Runs dry at

24 mi

start (full tank)153 mi

⚠ You run dry before the finish — add a stop earlier on the route.

Refuel — practice the decision, scored against the optimum

What does the Refuel puzzle teach?

Cross the distance in the fewest fill-ups: don't stop at the first low-tank station — bank the biggest refills you've already passed. That's the heap greedy.

Why do interviews ask about this?

Minimum refueling stops (LeetCode 871) — the max-heap greedy where you retroactively bank the largest passed refill instead of stopping at the first low-tank station.

How is it scored?

The engine computes the provably-optimal answer for the exact instance you played (dynamic programming, shortest-path, or exhaustive search — never a heuristic) and scores your attempt as a percentage of it. No login needed to see your score.

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Practice0:00

Refuel · D1

Cross 153 miles in the fewest fill-ups — a full tank goes 24 miles.

You start with a full tank. Each station you stop at refills you back to 24 miles of range. Pick the stations so you never run dry before the finish — using as few as possible.

Practice — no rating pressure. Get as close to the optimum as you can; each play teaches the pattern.

Runs dry at

24 mi

start (full tank)153 mi

⚠ You run dry before the finish — add a stop earlier on the route.