River Crossing River Jealous Husbands Expert — Set 38

Expert River Crossing Puzzle #38

Title

Expert River Crossing Puzzle #38

Scenario

Jealous Husbands

Narrative

Two couples must cross a river. The boat holds 2. Each husband is jealous: his wife must not be in the presence of another man unless her husband is also present.

Entities

• {"id":"h1","name":"Husband 1","icon":"\ud83d\udc68"}
• {"id":"w1","name":"Wife 1","icon":"\ud83d\udc69"}
• {"id":"h2","name":"Husband 2","icon":"\ud83d\udc68"}
• {"id":"w2","name":"Wife 2","icon":"\ud83d\udc69"}

BoatCapacity

2

Constraints

• The boat holds at most 2 people.
• No wife may be with another man unless her own husband is also present.
• At least one person must row each trip.

Question

Describe a valid sequence of crossings that gets everyone to the other side without violating any constraint. What is the minimum number of trips required?

Solution

• {"trip":1,"direction":"\u2192","carrying":["H1","W1"],"leftBank":"H2,W2","rightBank":"H1,W1","note":"Couple 1 cross."}
• {"trip":2,"direction":"\u2190","carrying":["H1"],"leftBank":"H1,H2,W2","rightBank":"W1","note":"H1 returns."}
• {"trip":3,"direction":"\u2192","carrying":["H2","W2"],"leftBank":"H1","rightBank":"H2,W2,W1","note":"Couple 2 cross."}
• {"trip":4,"direction":"\u2190","carrying":["W2"],"leftBank":"H1,W2","rightBank":"H2,W1","note":"W2 returns."}
• {"trip":5,"direction":"\u2192","carrying":["H1","W2"],"leftBank":"","rightBank":"All","note":"H1 and W2 cross. Done!"}

MinimumTrips

5

Hint

No hints are provided for this difficulty. Find the full solution on your own.

PartialSolutionHint