数据结构之多叉树的定义

利用List<？>构建树import java.util.ArrayList;import java.util.List;/** * 树节点 *  * @author Oliver *  */public class TreeNode {private String data;private TreeNode parentNode;private List<TreeNode> childList;public TreeNode() {initChildList();}public TreeNode(String data) {this.data = data;}/** * 返回当前节点的孩子节点，也可得到当前节点的兄弟节点 *  * @return List<TreeNode> */public List<TreeNode> getChildList() {return childList;}public void setChildList(List<TreeNode> childList) {this.childList = childList;}/** * 判断节点是否为叶子，是返回true，否则返回false *  * @return */public boolean isLeaf() {if (this.childList == null)return true;else {if (this.childList.isEmpty())return true;elsereturn false;}}/** * 判断两个节点是否含有相同的data * @param node * @return */protected boolean equals(TreeNode node) {if (this.getData().equals(node.getData()))return true;return false;}/** * 返回此节点的孩子节点列表中首次出现的指定元素的索引，或如果不包含元素，则返回-1 * @param node * @return */protected int indexOf(TreeNode node) {List<TreeNode> list = this.getChildList();int length = list.size();for (int i = 0; i < length; i++) {if (list.get(i).equals(node))return i;}return -1;}/*** * 添加一个孩子节点 */public void addChild(TreeNode childNode) {initChildList();// 如果存在该子节点，退出if (this.indexOf(childNode) >= 0)return;else {// 设置父亲节点childNode.setParentNode(this);this.childList.add(childNode);}}private void initChildList() {if (this.childList == null)this.childList = new ArrayList<TreeNode>();}/** * 返回当前节点的所有父辈节点 */public List<TreeNode> getElders() {List<TreeNode> elders = new ArrayList<TreeNode>();TreeNode parentNode = this.parentNode;if (parentNode == null) {return elders;} else {// 倒序插入elders.add(0, parentNode);elders.addAll(0, parentNode.getElders());return elders;}}/** * 返回当前节点的所有晚辈节点 */public List<TreeNode> getJuniors() {List<TreeNode> juniors = new ArrayList<TreeNode>();List<TreeNode> childList = this.getChildList();if (childList == null) {return juniors;} else {int length = childList.size();for (int i = 0; i < length; i++) {TreeNode junior = childList.get(i);juniors.add(junior);juniors.addAll(junior.getJuniors());}return juniors;}}/** * 层次遍历 *  * @param times */public void traverse(int times) {print(this, times);// 如果是叶子则返回if (this.isLeaf())return;int length = this.getChildList().size();times = times + 1;for (int i = 0; i < length; i++) {this.getChildList().get(i).traverse(times);}}private void print(TreeNode node, int times) {for (int i = 0; i < times; i++) {System.out.print("\t");}System.out.println(node.getData());}/** * 合并子节点 */public void mergeChildNode() {// 仅只有一个根节点或者是叶子节点if (this.isLeaf())return;List<TreeNode> childList = this.getChildList();int length = childList.size();if (length == 1) {TreeNode child = childList.get(0);// 合并dataString mergedData = this.getData() + child.getData();this.setData(mergedData);// 如果此时child已经是叶子节点了，即表示没有后代节点if (child.isLeaf()) {this.getChildList().clear();} else {// 修改节点的childListList<TreeNode> grandchildrenList = child.getChildList();this.getChildList().clear();for (TreeNode t : grandchildrenList) {t.setParentNode(this);this.getChildList().add(t);}this.mergeChildNode();}} else {for (int i = 0; i < length; i++) {childList.get(i).mergeChildNode();}}}/** * 删除合并后的子节点 *  * protected void deleteNode() { this.childList.clear(); } */public String getData() {return data;}public void setData(String data) {this.data = data;}public TreeNode getParentNode() {return parentNode;}public void setParentNode(TreeNode parentNode) {this.parentNode = parentNode;}}