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- import java.io.BufferedReader;
- import java.io.InputStreamReader;
- import java.util.StringTokenizer;
- import java.util.Iterator;
- import java.util.NoSuchElementException;
- interface Tree<E> {
- ////////////Accessors ////////////
- public Node<E> root();
- public Node<E> parent(Node<E> node);
- public int childCount(Node<E> node);
- ////////////Transformers ////////////
- public void makeRoot(E elem);
- public Node<E> addChild(Node<E> node, E elem);
- public void remove(Node<E> node);
- ////////////Iterator ////////////
- public Iterator<E> children(Node<E> node);
- }
- interface Node<E> {
- public E getElement();
- public void setElement(E elem);
- }
- class SLLTree<E> implements Tree<E> {
- public SLLNode<E> root;
- public SLLTree() {
- root = null;
- }
- public Node<E> root() {
- return root;
- }
- public Node<E> parent(Node<E> node) {
- return ((SLLNode<E>) node).parent;
- }
- public int childCount(Node<E> node) {
- SLLNode<E> tmp = ((SLLNode<E>) node).firstChild;
- int num = 0;
- while (tmp != null) {
- tmp = tmp.sibling;
- num++;
- }
- return num;
- }
- public void makeRoot(E elem) {
- root = new SLLNode<E>(elem);
- }
- public Node<E> addChild(Node<E> node, E elem) {
- SLLNode<E> tmp = new SLLNode<E>(elem);
- SLLNode<E> curr = (SLLNode<E>) node;
- tmp.sibling = curr.firstChild;
- curr.firstChild = tmp;
- tmp.parent = curr;
- return tmp;
- }
- public void remove(Node<E> node) {
- SLLNode<E> curr = (SLLNode<E>) node;
- if (curr.parent != null) {
- if (curr.parent.firstChild == curr) {
- // The node is the first child of its parent
- // Reconnect the parent to the next sibling
- curr.parent.firstChild = curr.sibling;
- } else {
- // The node is not the first child of its parent
- // Start from the first and search the node in the sibling list and remove it
- SLLNode<E> tmp = curr.parent.firstChild;
- while (tmp.sibling != curr) {
- tmp = tmp.sibling;
- }
- tmp.sibling = curr.sibling;
- }
- } else {
- root = null;
- }
- }
- class SLLTreeIterator<T> implements Iterator<T> {
- SLLNode<T> start, current;
- public SLLTreeIterator(SLLNode<T> node) {
- start = node;
- current = node;
- }
- public boolean hasNext() {
- return (current != null);
- }
- public T next() throws NoSuchElementException {
- if (current != null) {
- SLLNode<T> tmp = current;
- current = current.sibling;
- return tmp.getElement();
- } else {
- throw new NoSuchElementException();
- }
- }
- public void remove() {
- if (current != null) {
- current = current.sibling;
- }
- }
- }
- public Iterator<E> children(Node<E> node) {
- return new SLLTreeIterator<E>(((SLLNode<E>) node).firstChild);
- }
- void printTreeRecursive(Node<E> node, int level) {
- if (node == null)
- return;
- int i;
- SLLNode<E> tmp;
- for (i=0; i<level; i++)
- System.out.print(" ");
- System.out.println(node.getElement().toString());
- tmp = ((SLLNode<E>)node).firstChild;
- while (tmp != null) {
- printTreeRecursive(tmp, level+1);
- tmp = tmp.sibling;
- }
- }
- public void printTree() {
- printTreeRecursive(root, 0);
- }
- }
- class SLLNode<P> implements Node<P> {
- // Holds the links to the needed nodes
- public SLLNode<P> parent, sibling, firstChild;
- // Hold the data
- public P element;
- public SLLNode(P o) {
- element = o;
- parent = sibling = firstChild = null;
- }
- public P getElement() {
- return element;
- }
- public void setElement(P o) {
- element = o;
- }
- }
- public class WindowsExplorer {
- public static void main(String[] args) throws Exception {
- int i;
- BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
- int N = Integer.parseInt(br.readLine());
- String commands[] = new String[N];
- for (i=0; i<N; i++) {
- commands[i] = br.readLine();
- }
- br.close();
- SLLTree<String> tree = new SLLTree<String>();
- tree.makeRoot("c:");
- SLLNode<String> curr = (SLLNode<String>) tree.root();
- for(i = 0; i < commands.length; i++) {
- String str [] = commands[i].split("\\s+");
- switch(str[0]) {
- case "CREATE" : {
- String data = str[1];
- SLLNode<String> tmp = curr.firstChild;
- if(tmp == null || tmp.element.compareTo(data) > 0)
- tree.addChild(curr, data);
- else {
- SLLNode<String> toBeInserted = new SLLNode<String>(data);
- while(tmp.sibling != null) {
- if(tmp.sibling.element.compareTo(toBeInserted.element) > 0) {
- toBeInserted.sibling = tmp.sibling;
- tmp.sibling = toBeInserted;
- toBeInserted.parent = curr;
- break;
- }
- tmp = tmp.sibling;
- }
- toBeInserted.parent = curr;
- tmp.sibling = toBeInserted;
- }
- break;
- }
- case "OPEN" : {
- SLLNode<String> toOpen = curr.firstChild;
- while(toOpen != null) {
- if(toOpen.element.equals(str[1]))
- curr = toOpen;
- toOpen = toOpen.sibling;
- }
- break;
- }
- case "PATH" : {
- SLLNode<String> temp = curr;
- StringBuilder sb = new StringBuilder();
- while (temp != tree.root) {
- sb.insert(0, "\\");
- sb.insert(0, temp.element);
- temp = temp.parent;
- }
- sb.insert(0,"\\");
- sb.insert(0, tree.root.element);
- System.out.println(sb.toString());
- break;
- }
- case "BACK" : {
- curr = curr.parent;
- break;
- }
- case "PRINT" : {
- tree.printTree();
- break;
- }
- case "DELETE" : {
- SLLNode<String> tmp = curr;
- String data = str[1];
- if(tmp.element.equals(data)){
- curr = curr.parent;
- tree.remove(curr.firstChild);
- }
- else{
- tmp = tmp.firstChild;
- while(tmp != null){
- if(tmp.element.equals(data)){
- tree.remove(tmp);
- }
- tmp = tmp.sibling;
- }
- }
- break;
- }
- }
- }
- }
- }
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