AOC 2022 Day 20

/// Mix a list according to some rules
/// 1) Once.
/// 2) Ten times withe a key.
///

import 'package:collection/collection.dart';
import 'package:more/more.dart';

buildList(List<String> lines, {key = 1}) =>
    lines.map((e) => (int.parse(e) * key).toInt()).indexed().toList();

process(List<Indexed<int>> ns) {
  for (var n in 0.to(ns.length)) {
    var ix = ns.indexWhere((e) => e.index == n);
    var el = ns.removeAt(ix);
    ns.insert((ix + el.value) % ns.length, el);
  }
  return ns;
}

int calcAnswer(List<Indexed<int>> ns) {
  var ix = ns.indexWhere((e) => e.value == 0);
  return [1000, 2000, 3000].map((e) => ns[(ix + e) % ns.length].value).sum;
}

part1(List<String> lines) => calcAnswer(process(buildList(lines)));

part2(List<String> lines) => calcAnswer(
    0.to(10).fold(buildList(lines, key: 811589153), (s, _) => process(s)));