June 2018 Update

Task/Penneys-game/Kotlin/penneys-game.kotlin

@@ -0,0 +1,69 @@
+// version 1.2.10
+
+import java.util.Random
+
+val rand = Random()
+
+val optimum = mapOf(
+    "HHH" to "THH", "HHT" to "THH", "HTH" to "HHT", "HTT" to "HHT",
+    "THH" to "TTH", "THT" to "TTH", "TTH" to "HTT", "TTT" to "HTT"
+)
+
+fun getUserSequence(): String {
+    println("A sequence of three H or T should be entered")
+    var userSeq: String
+    do {
+        print("Enter your sequence: ")
+        userSeq = readLine()!!.toUpperCase()
+    }
+    while (userSeq.length != 3 || userSeq.any { it != 'H' && it != 'T' })
+    return userSeq
+}
+
+fun getComputerSequence(userSeq: String = ""): String {
+    val compSeq = if(userSeq == "")
+        String(CharArray(3) { if (rand.nextInt(2) == 0) 'T' else 'H' })
+    else
+        optimum[userSeq]!!
+    println("Computer's sequence: $compSeq")
+    return compSeq
+}
+
+fun main(args: Array<String>) {
+    var userSeq: String
+    var compSeq: String
+    val r = rand.nextInt(2)
+    if (r == 0) {
+        println("You go first")
+        userSeq = getUserSequence()
+        println()
+        compSeq = getComputerSequence(userSeq)
+    }
+    else {
+        println("Computer goes first")
+        compSeq = getComputerSequence()
+        println()
+        userSeq = getUserSequence()
+    }
+
+    println()
+    val coins = StringBuilder()
+    while (true) {
+        val coin = if (rand.nextInt(2) == 0) 'H' else 'T'
+        coins.append(coin)
+        println("Coins flipped: $coins")
+        val len = coins.length
+        if (len >= 3) {
+            val seq = coins.substring(len - 3, len)
+            if (seq == userSeq) {
+                println("\nYou win!")
+                return
+            }
+            else if (seq == compSeq) {
+                println("\nComputer wins!")
+                return
+            }
+        }
+        Thread.sleep(2000) // wait two seconds for next flip
+    }
+}