d21p2: clean up code and properly calculate previously manually-determined best key sequences

day22/d22p2.swift

@@ -8,7 +8,7 @@ func readInput(_ filePath: String) throws -> [Int] {
 func haggle(_ seeds: [Int]) -> [[Int]: [Int: Int]] {
     var bananas: [[Int]: [Int: Int]] = [:]
     for (monkey, seed) in seeds.enumerated() {
-        var prevs = [Int.min, Int.min, Int.min, Int.min]
+        var prevs = [monkey, seed, Int.min, Int.min]
         var lastPrice = seed
         for _ in 0..<2000 {
             var price = ((lastPrice << 6) ^ lastPrice) & 16777215