Weekly edition

Conference Deductions

Four developers gave talks on different topics and stayed at different hotels in four cities. Use the clues to match each person with their topic, hotel, and city.

Edition #1 medium Publish date: 2026-01-16
Scenario

Four developers gave talks on different topics and stayed at different hotels in four cities. Use the clues to match each person with their topic, hotel, and city.

Clues
  1. Alice did not stay at the Grand Hotel.
  2. The developer who spoke about MEV stayed at Harbor Suites.
  3. Bob spoke about DeFi.
  4. The speaker in Paris did not talk about Security.
  5. Carlos visited Oslo.
  6. The ZK Proofs talk was given by the developer staying at the Grand Hotel.
  7. Diana did not stay at Metro Inn.
  8. The developer in Lisbon stayed at Garden Place.
  9. The Security talk happened in Lisbon.
Solved

Explanation

Reveal the reasoning
  1. From clue 2, the MEV speaker must be the one staying at Harbor Suites. That identifies Diana's hotel once we pair her with MEV later.
  2. Clue 6 ties the ZK Proofs talk to the Grand Hotel, and clue 5 places Carlos in Oslo, so Carlos must be the ZK speaker at the Grand Hotel.
  3. Clue 3 fixes Bob as the DeFi speaker. Clue 4 rules out Security for the Paris speaker, so Bob fits Paris with DeFi.
  4. Clues 8 and 9 tie Lisbon to Garden Place and the Security talk, leaving Alice as the Security speaker in Lisbon, and Diana as the remaining MEV speaker in Prague at Harbor Suites.

Solution

Show solution mapping

Solve the puzzle to reveal the full mapping.

Order: Talk Topic / Hotel / City

  • Alice -> Security / Garden Place / Lisbon
  • Bob -> DeFi / Metro Inn / Paris
  • Carlos -> ZK Proofs / Grand Hotel / Oslo
  • Diana -> MEV / Harbor Suites / Prague

About this puzzle

  • Published: 2026-01-16
  • Validation: Build-time checks for a one-to-one solution mapping and consistent IDs.
  • Corrections: If you spot an issue, contact us with the puzzle date. See the editorial policy and the contact page.

FAQ

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Developer x Talk Topic

Developer ZK Proofs DeFi MEV Security
Alice
Bob
Carlos
Diana

Developer x Hotel

Developer Grand Hotel Metro Inn Harbor Suites Garden Place
Alice
Bob
Carlos
Diana

Developer x City

Developer Paris Lisbon Oslo Prague
Alice
Bob
Carlos
Diana

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Up next: Cafeteria Choices (2026-01-17)

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