Evenly Spaced Trees Evenly Spaced Trees
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You need to add some trees and keep them evenly spaced.

You are given a list of integers as an input value. This is the position of an existing tree. You must return the minimum number of additional trees needed so that they could be evenly spaced.

  • Positions of the existing trees are already sorted.
  • All positions of trees are integers.


evenly_spaced_trees([0, 2, 6]) == 1 # add to 4.
evenly_spaced_trees([1, 3, 6]) == 3 # add to 2, 4 and 5.
evenly_spaced_trees([0, 2, 4]) == 0 # no need to add.

Input: The position of the existing trees (a list of integers).

Output: The minimum number of additional trees (an integer).

How it is used:
Landscape design.


  • 0 ≤ Position of tree ≤ 100
  • 3 ≤ The existing trees

CheckiO Extensions

CheckiO Extensions allow you to use local files to solve missions. More info in a blog post.

In order to install CheckiO client you'll need installed Python (version at least 3.8)

Install CheckiO Client first:

pip3 install checkio_client

Configure your tool

checkio --domain=py config --key=

Sync solutions into your local folder

checkio sync

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checkio serv -d

Alternatevly, you can install Chrome extension or FF addon

checkio install-plugin
checkio install-plugin --ff
checkio install-plugin --chromium

Read more here about other functionality that the checkio client provides. Feel free to submit an issue in case of any difficulties.

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