Digital Plumber - Advent of Code - 20171212

ac20171212.js

let populateTree = function(nodesList) {
  let tree = nodesList
    .split('\n')
    .map(p => {
      let [node, children] = p.split(' <-> ');
      if (children) {
        children = children.split(', ');
      }
      return {
        id: parseInt(node.trim()),
        children: children
      };
    })
    .reduce((acc, n, i) => {
      acc.set(n.id, n);
      return acc;
    }, new Map());

  let keys = Array.from(tree.keys());
  keys.forEach(k => {
    let parentNode = tree.get(k);
    if (parentNode.children) {
      let childKeys = parentNode.children;
      parentNode.children = childKeys.map(c => tree.get(parseInt(c)));
    } else {
      parentNode.children = [];
    }
  });

  return tree;
};

let getGroupSize_1 = function(startNode, tree) {
  let visited = [];
  tree.forEach(function(value, key) {
    visited[key] = false;
  });

  let descendTree = function(node) {
    if (!visited[node.id]) {
      visited[node.id] = true;
      node.children.forEach(n => descendTree(n));
    }
  };
  descendTree(startNode);

  return visited.filter(v => v).length;
};

let getGroupSize = function(startNode, tree) {
  return getGroup(startNode, tree).length;
};

let getGroup = function(startNode, tree) {
  let visited = [];
  tree.forEach(function(value, key) {
    visited[key] = false;
  });

  let descendTree = function(node) {
    if (!visited[node.id]) {
      visited[node.id] = true;
      node.children.forEach(n => descendTree(n));
    }
  };
  descendTree(startNode);

  return visited.reduce((acc, n, i) => {
    if (n) {
      acc.push(i);
    }
    return acc;
  }, []);
};

let findNumberOfGroups = function(tree) {
  let visited = [];
  tree.forEach(function(value, key) {
    visited[key] = -1;
  });

  tree.forEach(function(node, key) {
    if (visited[key] == -1) {
      let descendants = getGroup(node, tree);
      descendants.forEach(v => {
        if (visited[v] == -1) {
          visited[v] = key;
        }
      });
    }
  });

  return visited.filter((v, i, arr) => arr.indexOf(v) == i).length;
};

let test = `0 <-> 2
1 <-> 1
2 <-> 0, 3, 4
3 <-> 2, 4
4 <-> 2, 3, 6
5 <-> 6
6 <-> 4, 5`;
test = populateTree(test);

let result = getGroupSize(test.get(0), test);
console.log(result);

result = findNumberOfGroups(test);
console.log(result);