Sakura Memory Gate
The koi festival gate cannot carry a giant guestbook. Give it a tiny petal memory that answers visitors in a blink!
🧠 Before we start
In the Halfway Hunt, you searched a sorted list for an exact answer. Today, a Bloom filter uses a tiny row of yes-or-no memory pads. It answers fast, but “maybe” is not the same as proof.
Stamp Aoi into petal memory
Two different lantern rules turn Aoi's name into pad numbers. Tap both glowing target pads; the filter stores only those tiny marks.
Welcome two more koi
Tap each visitor. Their two name stamps reuse or light pads. Notice: the filter remembers marks, not whole names.
Question the memory gate
Check both stamps for each name. One dark pad means definitely new. Two lit pads mean only maybe visited.
Debug the one-stamp gate
A rushed gate uses only one stamp. Nori lands on pad 1, which Aoi already lit, so the gate says “maybe.” Pick the repair that reduces mistaken maybes.
🌟 What you learned
- A Bloom filter is a compact way to remember whether items may have appeared.
- Several independent hash rules turn one item into several memory positions.
- If any required pad is off, the item is definitely new.
- If every required pad is on, the item may be known—but shared marks can create a false positive.
- More good stamp rules can reduce mistakes, while an exact list is still needed for proof.