Some board analysis for Pandemic (and Pandemic Legacy).

analyze.rb

require 'pp'

def compute(paths)
  out = []
  paths.keys.combination(3).each do |src|
    next if src.include?(:atla)
    next if src.include?(:hong)
    next if src.include?(:cair)
    next if src.include?(:saop)
    seen = [src]
    while seen.flatten.size < 48
      seen << seen.flatten.map{|k| paths[k]}.flatten.uniq - seen.flatten
    end

    next if seen.last.size > 7
    out << [seen.size-1, seen.first, seen.map(&:size)]
  end
  out.sort!.reject! { |dist, src, dest| dist > out.first.first}
  pp out.sort
  pp out.size
end

classic_paths = {
  :algi => [:madr, :pari, :ista, :cair],
  :atla => [:wash, :miam, :chic],
  :bagh => [:tehr, :riya, :cair, :ista, :kara],
  :bang => [:kolk, :hong, :hoch, :jaka, :chen],
  :beij => [:seou, :shan],
  :bogo => [:miam, :mexi, :lima, :buen, :saop],
  :buen => [:saop, :bogo],
  :cair => [:riya, :bagh, :ista, :algi, :khar],
  :chen => [:jaka, :kolk, :delh, :mumb, :bang],
  :chic => [:mont, :atla, :mexi, :losa, :sanf],
  :delh => [:kolk, :chen, :mumb, :kara, :tehr],
  :esse => [:stpe, :mila, :pari, :lond],
  :hoch => [:hong, :bang, :jaka, :mani],
  :hong => [:shan, :taip, :mani, :hoch, :bang, :kolk],
  :ista => [:stpe, :mosc, :bagh, :cair, :algi, :mila],
  :jaka => [:sydn, :hoch, :bang, :chen],
  :joha => [:khar, :kins],
  :kara => [:mumb, :delh, :tehr, :riya, :bagh],
  :khar => [:cair, :lago, :kins, :joha],
  :kins => [:lago, :khar, :joha],
  :kolk => [:hong, :bang, :chen, :delh],
  :lago => [:saop, :kins, :khar],
  :lima => [:sant, :bogo, :mexi],
  :lond => [:esse, :pari, :madr, :newy],
  :losa => [:mexi, :chic, :sanf, :sydn],
  :madr => [:saop, :newy, :lond, :pari, :algi],
  :mani => [:losa, :sydn, :hoch, :hong, :taip],
  :mexi => [:losa, :chic, :miam, :bogo, :lima],
  :miam => [:wash, :atla, :mexi, :bogo],
  :mila => [:ista, :pari, :esse],
  :mont => [:newy, :wash, :chic],
  :mosc => [:tehr, :ista, :stpe],
  :mumb => [:chen, :delh, :kara],
  :newy => [:lond, :madr, :wash, :mont],
  :osak => [:toky, :taip],
  :pari => [:mila, :esse, :lond, :madr, :algi],
  :riya => [:kara, :bagh, :cair],
  :sanf => [:chic, :losa, :mani, :toky],
  :sant => [:lima],
  :saop => [:buen, :bogo, :madr, :lago],
  :seou => [:toky, :shan, :beij],
  :shan => [:beij, :seou, :toky, :taip, :hong],
  :stpe => [:mosc, :ista, :esse],
  :sydn => [:losa, :mani, :jaka],
  :taip => [:osak, :shan, :hong, :mani],
  :tehr => [:delh, :kara, :bagh, :mosc],
  :toky => [:sanf, :osak, :shan, :seou],
  :wash => [:newy, :mont, :atla, :miam],
}

paths = {
  :algi => [:madr, :pari, :ista, :cair],
  :atla => [:wash, :miam, :chic],
  :bagh => [:tehr, :riya, :cair, :ista],
  :bang => [:kolk, :hong, :hoch, :jaka],
  :beij => [:seou, :shan],
  :bogo => [:miam, :mexi, :lima, :buen, :saop],
  :buen => [:joha, :saop, :bogo, :sant],
  :cair => [:riya, :bagh, :ista, :algi, :khar],
  :chen => [:jaka, :kolk, :delh, :mumb],
  :chic => [:mont, :atla, :mexi, :losa, :sanf],
  :delh => [:kolk, :chen, :mumb, :kara, :tehr],
  :esse => [:stpe, :mila, :pari, :lond],
  :hoch => [:hong, :bang, :jaka, :mani],
  :hong => [:shan, :taip, :mani, :hoch, :bang, :kolk],
  :ista => [:stpe, :mosc, :bagh, :cair, :algi, :mila],
  :jaka => [:sydn, :hoch, :bang, :chen],
  :joha => [:khar, :kins, :buen],
  :kara => [:mumb, :delh, :tehr, :riya],
  :khar => [:cair, :lago, :kins, :joha],
  :kins => [:lago, :khar, :joha],
  :kolk => [:hong, :bang, :chen, :delh],
  :lago => [:saop, :kins, :khar],
  :lima => [:sant, :bogo, :mexi, :losa],
  :lond => [:esse, :pari, :madr, :newy],
  :losa => [:lima, :mexi, :chic, :sanf, :sydn],
  :madr => [:saop, :newy, :lond, :pari, :algi],
  :mani => [:losa, :sydn, :hoch, :hong, :taip],
  :mexi => [:losa, :chic, :miam, :bogo, :lima],
  :miam => [:wash, :atla, :mexi, :bogo],
  :mila => [:ista, :pari, :esse],
  :mont => [:newy, :wash, :chic],
  :mosc => [:tehr, :ista, :stpe],
  :mumb => [:chen, :delh, :kara],
  :newy => [:lond, :madr, :wash, :mont],
  :osak => [:toky, :taip],
  :pari => [:mila, :esse, :lond, :madr, :algi],
  :riya => [:kara, :bagh, :cair],
  :sanf => [:chic, :losa, :mani, :toky],
  :sant => [:buen, :lima],
  :saop => [:buen, :bogo, :madr, :lago],
  :seou => [:toky, :shan, :beij],
  :shan => [:beij, :seou, :toky, :taip, :hong],
  :stpe => [:mosc, :ista, :esse],
  :sydn => [:losa, :mani, :jaka],
  :taip => [:osak, :shan, :hong, :mani],
  :tehr => [:delh, :kara, :bagh, :mosc],
  :toky => [:sanf, :osak, :shan, :seou],
  :wash => [:newy, :mont, :atla, :miam],
}

compute(paths)

legacy_results.txt

** Map changes between standard Pandemic and Legacy means this analysis is very different for both games.

Minimal coverage to put every city 3 steps away from a research station:
- Atlanta, Cairo, Manila

Minimal coverage to put almost every city 2 steps away from a research station:
- Atlanta, Hong Kong, Sao Paulo, Istanbul/Cairo: only 2 cities at three steps.

Other building types are not given the free Atlanta start, and can get reasonable coverage with just three stations:
- Cairo, Hong Kong, Mexico City: only 4 cities at three steps
- Cairo, Hong Kong, Miami: only 5 cities at three steps
Avoiding top cities for Research stations (so you don't lose both if city is lost):
- Algiers, Kolkata, Mexico City: only 7 cities at three steps
- Delhi, Madrid, San Francisco: only 7 cities at three steps