Added 27 solutions
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rshaghoulian
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// Author: Rodney Shaghoulian
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// Github: github.com/rshaghoulian
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// HackerRank: hackerrank.com/rshaghoulian
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import java.util.ArrayList;
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import java.io.*;
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import java.util.*;
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import java.text.*;
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import java.math.*;
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import java.util.regex.*;
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import java.util.ArrayList;
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import java.util.Scanner;
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enum Color {
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RED, GREEN
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}
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abstract class Tree {
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private int value;
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private Color color;
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private int depth;
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public Tree(int value, Color color, int depth) {
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this.value = value;
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this.color = color;
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this.depth = depth;
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}
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public int getValue() {
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return value;
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}
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public Color getColor() {
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return color;
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}
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public int getDepth() {
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return depth;
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}
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public abstract void accept(TreeVis visitor);
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}
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class TreeNode extends Tree {
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private ArrayList<Tree> children = new ArrayList<>();
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public TreeNode(int value, Color color, int depth) {
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super(value, color, depth);
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}
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public void accept(TreeVis visitor) {
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visitor.visitNode(this);
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for (Tree child : children) {
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child.accept(visitor);
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}
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}
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public void addChild(Tree child) {
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children.add(child);
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}
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}
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class TreeLeaf extends Tree {
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public TreeLeaf(int value, Color color, int depth) {
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super(value, color, depth);
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}
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public void accept(TreeVis visitor) {
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visitor.visitLeaf(this);
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}
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}
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abstract class TreeVis {
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public abstract int getResult();
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public abstract void visitNode(TreeNode node);
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public abstract void visitLeaf(TreeLeaf leaf);
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}
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// Useful tutorial for Visitor Pattern:
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// https://www.tutorialspoint.com/design_pattern/visitor_pattern.htm
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//
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// I recommend skipping this problem since it's more about creating a
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// tree in an obscure format than it is about Visitor patterns.
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class SumInLeavesVisitor extends TreeVis {
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private int result = 0;
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public int getResult() {
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return result;
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}
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public void visitNode(TreeNode node) {
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// do nothing
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}
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public void visitLeaf(TreeLeaf leaf) {
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result += leaf.getValue();
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}
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}
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class ProductOfRedNodesVisitor extends TreeVis {
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private long result = 1;
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private final int M = 1000000007;
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public int getResult() {
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return (int) result;
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}
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public void visitNode(TreeNode node) {
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if (node.getColor() == Color.RED) {
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result = (result * node.getValue()) % M;
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}
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}
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public void visitLeaf(TreeLeaf leaf) {
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if (leaf.getColor() == Color.RED) {
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result = (result * leaf.getValue()) % M;
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}
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}
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}
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class FancyVisitor extends TreeVis {
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private int nonLeafEvenDepthSum = 0;
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private int greenLeavesSum = 0;
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public int getResult() {
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return Math.abs(nonLeafEvenDepthSum - greenLeavesSum);
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}
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public void visitNode(TreeNode node) {
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if (node.getDepth() % 2 == 0) {
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nonLeafEvenDepthSum += node.getValue();
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}
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}
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public void visitLeaf(TreeLeaf leaf) {
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if (leaf.getColor() == Color.GREEN) {
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greenLeavesSum += leaf.getValue();
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}
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}
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}
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public class Solution {
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private static int [] values;
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private static Color [] colors;
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private static HashMap<Integer, HashSet<Integer>> map;
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public static Tree solve() {
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Scanner scan = new Scanner(System.in);
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int numNodes = scan.nextInt();
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/* Handle 1-node tree */
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if (numNodes == 1) {
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return new TreeLeaf(values[0], colors[0], 0);
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}
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/* Read and save nodes and colors */
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values = new int[numNodes];
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colors = new Color[numNodes];
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map = new HashMap<>(numNodes);
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for (int i = 0; i < numNodes; i++) {
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values[i] = scan.nextInt();
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}
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for (int i = 0; i < numNodes; i++) {
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colors[i] = scan.nextInt() == 0 ? Color.RED : Color.GREEN;
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}
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/* Save edges */
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for (int i = 0; i < numNodes - 1; i++) {
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int u = scan.nextInt();
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int v = scan.nextInt();
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/* Edges are undirected: Add 1st direction */
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HashSet<Integer> uNeighbors = map.get(u);
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if (uNeighbors == null) {
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uNeighbors = new HashSet<>();
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}
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uNeighbors.add(v);
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map.put(u, uNeighbors);
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/* Edges are undirected: Add 2nd direction */
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HashSet<Integer> vNeighbors = map.get(v);
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if (vNeighbors == null) {
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vNeighbors = new HashSet<>();
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}
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vNeighbors.add(u);
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map.put(v, vNeighbors);
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}
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scan.close();
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/* Create Tree */
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TreeNode root = new TreeNode(values[0], colors[0], 0);
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addChildren(root, 1);
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return root;
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}
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/* Recursively adds children of a TreeNode */
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private static void addChildren(TreeNode parent, Integer parentNum) {
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/* Get HashSet of children and loop through them */
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for (Integer treeNum : map.get(parentNum)) {
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map.get(treeNum).remove(parentNum); // removes the opposite arrow direction
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/* Add child */
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HashSet<Integer> grandChildren = map.get(treeNum);
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boolean childHasChild = (grandChildren != null && !grandChildren.isEmpty());
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Tree tree;
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if (childHasChild) {
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tree = new TreeNode(values[treeNum - 1], colors[treeNum - 1], parent.getDepth() + 1);
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} else {
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tree = new TreeLeaf(values[treeNum - 1], colors[treeNum - 1], parent.getDepth() + 1);
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}
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parent.addChild(tree);
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/* Recurse if necessary */
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if (tree instanceof TreeNode) {
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addChildren((TreeNode) tree, treeNum);
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}
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}
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}
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public static void main(String[] args) {
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Tree root = solve();
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SumInLeavesVisitor vis1 = new SumInLeavesVisitor();
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ProductOfRedNodesVisitor vis2 = new ProductOfRedNodesVisitor();
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FancyVisitor vis3 = new FancyVisitor();
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root.accept(vis1);
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root.accept(vis2);
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root.accept(vis3);
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int res1 = vis1.getResult();
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int res2 = vis2.getResult();
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int res3 = vis3.getResult();
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System.out.println(res1);
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System.out.println(res2);
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System.out.println(res3);
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}
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}
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