Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Community Proposals
Community Proposals
tag:snake search within a tag
answers:0 unanswered questions
user:xxxx search by author id
score:0.5 posts with 0.5+ score
"snake oil" exact phrase
votes:4 posts with 4+ votes
created:<1w created < 1 week ago
post_type:xxxx type of post
Search help
Notifications
Mark all as read See all your notifications »
Incubator Q&A

Welcome to the staging ground for new communities! Each proposal has a description in the "Descriptions" category and a body of questions and answers in "Incubator Q&A". You can ask questions (and get answers, we hope!) right away, and start new proposals.

Are you here to participate in a specific proposal? Click on the proposal tag (with the dark outline) to see only posts about that proposal and not all of the others that are in progress. Tags are at the bottom of each post.

Fill the circles so that consecutive numbers are not adjacent Question

+2
−0

In each puzzle, fill the circles using all the positive integers 1, 2, 3, ... n, where n is the number of circles in such a way that consecutive numbers are NOT in circles that are joined with a line.

Sample puzzle (n=7):

Sample puzzle with 7 circles

Sample solution:

Click here to reveal

Solution with numbers filled in


Main puzzle (n=9):

Main puzzle with 9 circles

History

0 comment threads

1 answer

+3
−0
Answer
Solution method

First note the number of connections each node has.

Since the numbers at the end of the sequence have only one connection instead of two for inner numbers, place the end numbers in the two nodes with the most connections. That fixes 1 and 9.

Each of the 1 and 9 nodes are connected to all others except one. That forces 8 and 2.

You now have 3 4 5 6 7 left to place. The remaining nodes have 3, 6, 6, 3, and 4 connections. Therefore it makes sense to try placing 3 and 7 in the two nodes with 6 connections. Note that these can only go one way due to one of these nodes being connected to 2 and the other to 8.

Left to place are 4 5 6. The node at the very bottom touches both 3 and 7, so that node must be 5.

The remaining 4 and 6 can only go one way since one of the open nodes is next to 3 and the other next to 7.

History

1 comment thread

Oops! (2 comments)

Sign up to answer this question »