AOC2020/aoc2020/lib/aoc20201207.dart

import 'package:aoc2020/aocbase.dart';
import 'package:aoc2020/model/readdata.dart';

class Bag {
  final String color;
  int count;
  Bag parent;
  List<Bag> children;

  Bag({this.color, this.parent, this.count, List<Bag> children}) : children = [];

  Bag.copy(Bag source)
      : color = source.color,
        count = source.count,
        parent = Bag(color: source.color),
        children = List.from(source.children);

  @override
  String toString() => 'Bag($color, parent: ${parent?.color ?? 'TOP'}, count: $count, with: ${children.map((child) => '${child.count}:${child.color}')})';
}

class AOC20201207 extends AOCBase {
// Create a List of all the leaves, then piece together all the trees

  List<Bag> leaves;
  List<Bag> trees;

  void parseLine(String line) {
    // Split line by "bags contain" first part is color of holding bag, second part is contents
    // split contents by ", " List of number and color of content bag(s)
    var split_one = line.split('bags contain');
    var holdingBagColor = split_one[0].trim();
    var holdingBag = Bag(color: holdingBagColor);
    var split_two = split_one[1].substring(0, split_one[1].length - 1).trim().split(',');
    for (var _bag in split_two) {
      var split_three = _bag.trim().split(' ');
      if (split_three[0] != 'no') {
        var numBags = int.parse(split_three[0]);
        var childColor = split_three[1] + ' ' + split_three[2];
        var child = Bag(color: childColor);
        child.count = numBags;
        child.parent = holdingBag;
        // leaves.add(child);
        holdingBag.children.add(child);
      }
    }
    leaves.add(holdingBag);
  }

  Set<String> findTops() {
    var leavesWithParents = <String>{};
    var allLeaves = <String>{};
    for (var leaf in leaves.where((bag) => bag.children.isNotEmpty)) {
      leavesWithParents.addAll(leaf.children.map((child) => child.color));
    }
    allLeaves.addAll(leaves.map((leaf) => leaf.color));
    return allLeaves.difference(leavesWithParents);
  }

  Bag constructTreeFromTopBag({Bag top, int count, int level = 0}) {
    // var topBag = leaves.firstWhere((bag) => bag.color == top);
    var _newBag = top;
    var _newChildren = <Bag>[];
    // print(''.padLeft(level * 4) + 'Top = $top');
    for (var child in top.children) {
      var _firstChild = leaves.firstWhere((bag) => bag.color == child.color, orElse: () => null);
      var _newChild = Bag.copy(_firstChild);
      if (_newChild != null) {
        _newChild.parent = top;
        _newChild.count = child.count;
        // print(''.padLeft(level * 4) + 'newChild = $_newChild  $child');
        _newChildren.add(constructTreeFromTopBag(top: _newChild, level: level + 1));
      }
    }
    _newBag.children = _newChildren;
    // print(''.padLeft(level * 4) + 'newBag = $_newBag');
    return _newBag;
  }

  List<Bag> findAll({String color, Set<String> tops}) {
    var _bags = <Bag>[];

    void _find({String findColor, Bag findTop}) {
      if (findTop.color == findColor) _bags.add(findTop);
      for (var child in findTop.children) {
        _find(findColor: findColor, findTop: child);
      }
    }

    for (var top in tops) {
      var topBag = leaves.firstWhere((bag) => bag.color == top);
      _find(findColor: color, findTop: topBag);
    }
    return _bags;
  }

  int countContents(Bag top) {
    var _count = 0;
    if (top.children.isEmpty) return 0;
    for (var child in top.children) {
      _count += child.count;
      _count += child.count * countContents(child);
    }
    return _count;
  }

  @override
  Future<void> a({bool test}) async {
    var mylist = await ReadData.readFile<String>(classString, test: test);
    leaves = []; // Zero out list
    trees = [];

    for (var line in mylist) {
      parseLine(line);
    }

    var tops = findTops();
    for (var top in tops) {
      var topBag = leaves.firstWhere((bag) => bag.color == top);
      trees.add(constructTreeFromTopBag(top: topBag));
    }
    // print('Number of Tops = ${tops.length}');

    var _uniqueParents = <String>{};
    void _setUniqueParents(Bag bag) {
      if (bag.parent != null) {
        _uniqueParents.add(bag.parent.color);
        _setUniqueParents(bag.parent);
      }
    }

    _uniqueParents = {};
    for (var bag in findAll(color: 'shiny gold', tops: tops)) {
      _setUniqueParents(bag);
    }

    answerA = _uniqueParents.length;
  }

  @override
  Future<void> b({bool test}) async {
    var mylist = await ReadData.readFile<String>(classString, test: test);
    leaves = []; // Zero out list
    trees = [];

    for (var line in mylist) {
      parseLine(line);
    }

    var tops = findTops();
    for (var top in tops) {
      var topBag = leaves.firstWhere((bag) => bag.color == top);
      trees.add(constructTreeFromTopBag(top: topBag));
    }
    // print('Number of Tops = ${tops.length}');

    var _bags = findAll(color: 'shiny gold', tops: tops);
    var _shiny = _bags.first;

    answerB = countContents(_shiny);
  }
}