River Crossing River Farmer Puzzle Easy — Set 61

Easy River Crossing Puzzle #61

Title

Easy River Crossing Puzzle #61

Scenario

Farmer's Problem

Narrative

A farmer must transport a dog, a cat, and a mouse across a river. The boat holds only the farmer plus one animal.

Entities

• {"id":"farmer","name":"Farmer","icon":"\ud83d\udc68\u200d\ud83c\udf3e"}
• {"id":"dog","name":"Dog","icon":"\ud83d\udc15"}
• {"id":"cat","name":"Cat","icon":"\ud83d\udc08"}
• {"id":"mouse","name":"Mouse","icon":"\ud83d\udc2d"}

BoatCapacity

1

Constraints

• Dog and cat cannot be left alone (the dog will chase the cat).
• Cat and mouse cannot be left alone (the cat will eat the mouse).

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":["Cat"],"leftBank":"Dog,Mouse","rightBank":"Cat","note":"Take the cat first."}
• {"trip":2,"direction":"\u2190","carrying":[],"leftBank":"Dog,Mouse,Farmer","rightBank":"Cat","note":"Return empty."}
• {"trip":3,"direction":"\u2192","carrying":["Dog"],"leftBank":"Mouse","rightBank":"Cat,Dog","note":"Take the dog."}
• {"trip":4,"direction":"\u2190","carrying":["Cat"],"leftBank":"Mouse,Cat","rightBank":"Dog","note":"Bring cat back."}
• {"trip":5,"direction":"\u2192","carrying":["Mouse"],"leftBank":"Cat","rightBank":"Dog,Mouse","note":"Take the mouse."}
• {"trip":6,"direction":"\u2190","carrying":[],"leftBank":"Cat,Farmer","rightBank":"Dog,Mouse","note":"Return empty."}
• {"trip":7,"direction":"\u2192","carrying":["Cat"],"leftBank":"","rightBank":"All","note":"Take the cat. Done!"}

MinimumTrips

7

Hint

The first 3 move(s) of the solution are shown below to help you start.

PartialSolutionHint

• {"trip":1,"direction":"\u2192","carrying":["Cat"],"leftBank":"Dog,Mouse","rightBank":"Cat","note":"Take the cat first."}
• {"trip":2,"direction":"\u2190","carrying":[],"leftBank":"Dog,Mouse,Farmer","rightBank":"Cat","note":"Return empty."}
• {"trip":3,"direction":"\u2192","carrying":["Dog"],"leftBank":"Mouse","rightBank":"Cat,Dog","note":"Take the dog."}