TreeSearch.java
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import java.util.ArrayList; class Tree { private class TreeNode { int value; ArrayList<TreeNode> children; public TreeNode(int value){ this.value = value; children = new ArrayList<>(); } public String toString(){ return "TreeNode: " + value; } } private TreeNode root; public boolean BFS(int v){ LinkedQueue<TreeNode> toVisit = new LinkedQueue<TreeNode>(root); while (!toVisit.isEmpty()){ System.out.println("toVisit: " + toVisit); TreeNode curr = toVisit.dequeue(); if (curr.value == v) return true; for (TreeNode c : curr.children) toVisit.enqueue(c); } return false; } public boolean DFS(int v){ LinkedStack<TreeNode> toVisit = new LinkedStack<TreeNode>(root); while (!toVisit.isEmpty()){ System.out.println("toVisit: " + toVisit); TreeNode curr = toVisit.pop(); if (curr.value == v) return true; for (TreeNode c : curr.children) toVisit.push(c); } return false; } private boolean recursiveDFSHelper(int v, TreeNode n){ System.out.println("Visiting: " + n); if (n.value == v) return true; for (TreeNode c : n.children) if(recursiveDFSHelper(v, c)) return true; return false; } public boolean recursiveDFS(int v){ return recursiveDFSHelper(v, root); } // It's a silly tree because this isn't really hierarchical // data! So, we end up doing exhaustive search (Ugh!) public void populateSillyTree(){ root = new TreeNode(2); TreeNode n7 = new TreeNode(7); TreeNode n5 = new TreeNode(5); TreeNode n9 = new TreeNode(9); TreeNode n4 = new TreeNode(4); TreeNode n11 = new TreeNode(11); TreeNode n3 = new TreeNode(3); TreeNode n6 = new TreeNode(6); root.children.add(n7); root.children.add(n5); n7.children.add(n9); n5.children.add(n4); n5.children.add(n11); n4.children.add(n3); n4.children.add(n6); } } public class TreeSearch { public static void main(String[] args){ System.out.println("--- BFS for 3 ---"); Tree t = new Tree(); t.populateSillyTree(); t.BFS(3); System.out.println("--- DFS for 3 ---"); t.DFS(3); System.out.println("--- Recursive DFS for 3 ---"); t.recursiveDFS(3); } } |