Data update

Task/Evolutionary-algorithm/Kotlin/evolutionary-algorithm.kts

@@ -0,0 +1,34 @@
+import java.util.*
+
+val target = "METHINKS IT IS LIKE A WEASEL"
+val validChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ "
+
+val random = Random()
+
+fun randomChar() = validChars[random.nextInt(validChars.length)]
+fun hammingDistance(s1: String, s2: String) =
+        s1.zip(s2).map { if (it.first == it.second) 0 else 1 }.sum()
+
+fun fitness(s1: String) = target.length - hammingDistance(s1, target)
+
+fun mutate(s1: String, mutationRate: Double) =
+        s1.map { if (random.nextDouble() > mutationRate) it else randomChar() }
+                .joinToString(separator = "")
+
+fun main(args: Array<String>) {
+    val initialString = (0 until target.length).map { randomChar() }.joinToString(separator = "")
+
+    println(initialString)
+    println(mutate(initialString, 0.2))
+
+    val mutationRate = 0.05
+    val childrenPerGen = 50
+
+    var i = 0
+    var currVal = initialString
+    while (currVal != target) {
+        i += 1
+        currVal = (0..childrenPerGen).map { mutate(currVal, mutationRate) }.maxBy { fitness(it) }!!
+    }
+    println("Evolution found target after $i generations")
+}