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Silly programming problem: add either +, - or nothing between 1 to 9, which combinations yields 100?
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import javax.script.ScriptEngineManager | |
// I *could* write an evaluation engine by hand, since it's only + and - it would be dead easy, but... not this time... | |
val e = new ScriptEngineManager().getEngineByName("javascript") | |
val operators:Seq[String] = Seq("+","-","") | |
val choose1 = for { | |
c1 <- operators | |
c2 <- operators | |
c3 <- operators | |
c4 <- operators | |
c5 <- operators | |
c6 <- operators | |
c7 <- operators | |
c8 <- operators | |
stringRep = s"1${c1}2${c2}3${c3}4${c4}5${c5}6${c6}7${c7}8${c8}9" | |
result = e.eval(stringRep).asInstanceOf[Double].toInt | |
if result == 100 | |
} yield { | |
stringRep | |
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
import javax.script.ScriptEngineManager | |
// I *could* write an evaluation engine by hand, since it's only + and - it would be dead easy, but... not this time... | |
val e = new ScriptEngineManager().getEngineByName("javascript") | |
val operators:Seq[String] = Seq("+","-","") | |
def operatorPermutations(position:Int):Seq[String] = { | |
if (position > 1) { | |
for { | |
curOp <- operators | |
choose1 = operatorPermutations(position-1) | |
choice<-choose1 | |
strRes = choice + curOp + position.toString | |
} yield { | |
strRes | |
} | |
} else { | |
Seq("1") | |
} | |
} | |
for { | |
option <- operatorPermutations(9) | |
result = e.eval(option).asInstanceOf[Double].toInt | |
if result == 100 | |
} yield { | |
option | |
} |
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