From e532f86d983251c7f4c3d77752d7c75d75933762 Mon Sep 17 00:00:00 2001
From: Tom Larsen <tom_larsen@msn.com>
Date: Wed, 30 Nov 2022 21:21:54 -0600
Subject: [PATCH] Incomplete attempt at solving Day 14, Part 2 Advent of Code
 2021.

---
 2021/day14-2/src/main/kotlin/Main.kt        | 103 ++++++++++++++++++++
 2021/day14-2/src/main/resources/small_input |  18 ++++
 2 files changed, 121 insertions(+)
 create mode 100644 2021/day14-2/src/main/kotlin/Main.kt
 create mode 100644 2021/day14-2/src/main/resources/small_input

diff --git a/2021/day14-2/src/main/kotlin/Main.kt b/2021/day14-2/src/main/kotlin/Main.kt
new file mode 100644
index 0000000..637b1d8
--- /dev/null
+++ b/2021/day14-2/src/main/kotlin/Main.kt
@@ -0,0 +1,103 @@
+import java.io.File
+
+fun main(args: Array<String>) {
+    println("AOC 2021, Day 14.2 starting!!!!")
+
+    val polymerBuilder = PolymerBuilder()
+    // args[0] should read /Users/tlarsen/src/adventofcode/2021/DAY-PART/src/main/resources
+    File(args[0]).forEachLine {
+        if (polymerBuilder.polymerPairOfChar.isEmpty()) {
+            polymerBuilder.addTemplate(it)
+        } else if (it.isNotEmpty()) {
+            polymerBuilder.addRule(it)
+        }
+    }
+
+    println("Original polymer: ${polymerBuilder.polymerPairOfChar}")
+    // build 10 times
+    var polymer = ""
+    for(i in 1..10) {
+        polymer = polymerBuilder.build()
+        //println("After step $i, the polymer is: $polymer")
+        println("After step $i, the polymer is X long.")
+    }
+    println("Stats on the last polymer: ${polymer.length}")
+    val chemCounter = HashMap<Char, Long>()
+    for(ch in polymer) {
+        if(!chemCounter.containsKey(ch)) {
+            chemCounter[ch] = 0
+        }
+        chemCounter[ch] = chemCounter[ch]!! + 1L
+    }
+
+    println("Counts: $chemCounter")
+
+    var mostCommonCount = 0L
+    var leastCommonCount = 0L
+    for(count in chemCounter.values) {
+        if(mostCommonCount == 0L) {
+            mostCommonCount = count
+        } else {
+            mostCommonCount = Math.max(count, mostCommonCount)
+        }
+        if(leastCommonCount == 0L) {
+            leastCommonCount = count
+        } else {
+            leastCommonCount = Math.min(count, leastCommonCount)
+        }
+    }
+
+    println("Most Common Count : $mostCommonCount")
+    println("Least Common Count: $leastCommonCount")
+    println("Difference        : ${mostCommonCount - leastCommonCount}")
+
+    println("AOC 2021, Day 14.2 complete!!!!")
+}
+
+data class MyPair<L: Any, R: Any> constructor(val left:L, val right:R)
+
+data class PairOfChar constructor(val left: Char, val right: Char)
+
+class PolymerBuilder {
+    var polymerPairOfChar = ArrayList<MyPair<Char, Char>>()
+        private set
+    var rules = HashMap<String, Char>()
+        private set
+
+    fun build() : String {
+        val newPolymer = ArrayList<PairOfChar>()
+
+        for(i in 0 until polymerPairOfChar.size - 1) {
+            var copy = true
+            for(rule in rules.keys) {
+                if((polymer[i] == rule[0]) && (polymer[i + 1] == rule[1])) {
+                    newPolymer += polymer[i]
+                    newPolymer += rules[rule]!!
+
+                    copy = false
+                }
+            }
+            if(copy) {
+                newPolymer += polymer[i]
+            }
+        }
+        // the loop is always - 1 so copy forward the very last character
+        newPolymer += polymer.last()
+
+        polymer = newPolymer
+
+        return String(newPolymer.toCharArray())
+    }
+
+
+    fun addTemplate(templ: String) {
+        for(i in 0 until templ.length - 1) {
+            polymerPairOfChar.add(PairOfChar(templ[i], templ[i + 1]))
+        }
+    }
+
+    fun addRule(rule:String) {
+        val splitPointer = rule.split("->") // split line left -> right
+        rules[splitPointer[0].trim()] = splitPointer[1].trim()[0]
+    }
+}
\ No newline at end of file
diff --git a/2021/day14-2/src/main/resources/small_input b/2021/day14-2/src/main/resources/small_input
new file mode 100644
index 0000000..6c1c3a1
--- /dev/null
+++ b/2021/day14-2/src/main/resources/small_input
@@ -0,0 +1,18 @@
+NNCB
+
+CH -> B
+HH -> N
+CB -> H
+NH -> C
+HB -> C
+HC -> B
+HN -> C
+NN -> C
+BH -> H
+NC -> B
+NB -> B
+BN -> B
+BB -> N
+BC -> B
+CC -> N
+CN -> C
\ No newline at end of file