Simple math simulation for risk legacy combat

risk.rb

require 'pp'
require 'csv'

def attack(attackers, defenders, defending=2)
  while defenders > 0 and attackers > 1
    this_attack = [attackers-1, 3].min
    this_defense = [defenders, defending].min

    attack = ([0]*this_attack).map{rand(6)+1}.sort
    defense = ([0]*this_defense).map{rand(6)+1}.sort

    # Bunker
    #defense[-1] = [defense[-1]+1, 6].min
    # Ammo Shortage
    #defense[-1] = [defense[-1]-1, 1].max

    if attack.pop > defense.pop
      defenders -= 1
    else
      attackers -= 1
    end

    if attack.any? and defense.any?
      if (attack.pop > defense.pop)
        defenders -= 1
      else
        attackers -= 1
      end
    end
  end
  [attackers, defenders]
end

def simulate(n, a, d, s)
  results = Hash.new{|h,k| h[k] = 0}
  n.times do
    result = attack(a,d,s)
    results[result] += 1
  end
  report(results)
end

def report(results)
  keys = results.keys.sort_by{|key| [key[0], -key[1]] }
  max = results.values.max.to_f
  keys.each do |key|
    scale = (results[key] / max) * 50
    #puts "%2d %2d: %5d %s" % [key.first, key.last, results[key], '#' * scale]
    puts [key.first, key.last, results[key]].to_csv
  end
  puts
end

simulate(100_000, 15, 5, 2)
simulate(100_000, 15, 5, 1)