Die Roller

class Dice
    attr_reader :die, :maxSum, :minSum

    def initialize(*args)
        @die = args.dup.freeze
        @values = Array.new(@die.size, 1)
        @maxSum = @die.inject(:+)
        @minSum = @die.size
    end

    def roll
        @die.map { |d| rand(d) + 1 }
    end

    def roll_sum(num = 0)
        t = roll.sort

        if (num > 0) then
            t.slice!(0, num)
        elsif (num < 0) then
            t.slice!(num, num.abs)
        end

        t.inject { |sum, x| sum + x }
    end

    def roll_assoc
        @die.map { |d| [rand(d) + 1, d] }
    end

    def roll_sorted
        roll_assoc.sort do |a, b|
            if (a[0] == b[0]) then
                a[1] <=> b[1]
            else
                a[0] <=> b[0]
            end
        end
    end

    def incr
        i = 0
        while (i < @die.size) do
            @values[i] += 1
            if (@values[i] > @die[i]) then
                @values[i] = 1
                i += 1
            else
                break
            end
        end
    end

    def sum
        @values.inject(:+)
    end

    def min?
        sum == @minSum
    end

    def max?
        sum == @maxSum
    end

    def max
        @values.max
    end

    def min
        @values.min
    end

    def inspect
        @values
    end
end

myDice = Dice.new(20, 20)
maxRolls = Hash.new(0)
minRolls = Hash.new(0)
totalRolls = 0

loop do
    maxRolls[myDice.max] += 1
    minRolls[myDice.min] += 1

    totalRolls += 1

    myDice.incr
    break if (myDice.min?)
end

puts "#{totalRolls} total rolls"

difficulty = 17
difficultyTotal = 0

maxRolls.each_pair do |roll, total|
    printf("%2d: %4d (%.2f%%)\n", roll, total, total.fdiv(totalRolls) * 100)
    difficultyTotal += total if roll >= difficulty
end

printf("%.2f%% success vs (%d)\n", difficultyTotal.fdiv(totalRolls), difficulty)