discrete and cominatorial math chapter 1_1
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#/usr/bin/env julia
function trafficMethod( way::String, from::String = "Hsinchu", to::String = "Taipei" )::Function
return function ()
println("form $from to $to by $way")
end
end
function count( a::Array, b::Array, ;rule = "product" )::Integer
countA = length(a)
countB = length(b)
if countA <= 0 || countB <= 0
error("illegal input")
end
if rule == "sum"
return countA + countB
end
if rule == "product"
return countA * countB
end
error("I don't know the option of $rule mean !\n")
end
println("""
Ex:
Frank wants to go to Taipei.
He can choose from bus services or train services to head from home to Hsinchu .
From there, he can choose from 2 bus services or 3 train services to head to Taipei.
{ bus: Kuo-Kuang Greyhound-Line , train: Amtrak Krtco Metro-Taipei }
How many ways are there for Hsinchu to get to Taipei?
"""
)
byBus = [ trafficMethod("Kuo-Kuang") trafficMethod("Greyhound-Line") ]
byTrain = [ trafficMethod("Amtrak") trafficMethod("Krtco") trafficMethod("Metro-Taipei") ]
println( "We have $(count( byBus, byTrain , rule = "sum" ) ) way to reach it\n" )
println("The rule of product");
player = [ "rock" "paper" "scissors" ]
println("Ex:\n How many situation of \"rock paper scissors\" game for two player")
println("We have $( count( player, player ) ) situation")
Julia
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