二叉树java遍历实现
假设二叉树如图:
import java.util.ArrayList; import java.util.List; import org.junit.Test; public class MyTree { private Node root = null; public MyTree() { init(); } private List<Node> list = new ArrayList<Node>(); private void init() { Node e = new Node("E", null, null); Node d = new Node("D", null, null); Node b = new Node("B", d, e); Node c = new Node("C", null, null); Node a = new Node("A", b, c); root = a; } private class Node { private String data; private Node lChild; private Node rChild; public Node(String data, Node lChild, Node rChild) { this.data = data; this.lChild = lChild; this.rChild = rChild; } } /** * 深度遍历 * * */ public int getTreeDepth(Node node) { if (node.lChild == null && node.rChild == null) { return 1; } int left = 0, right = 0; if (node.lChild != null) { left = getTreeDepth(node.lChild); } if (node.rChild != null) { right = getTreeDepth(node.rChild); } return left > right ? left + 1 : right + 1; } /** * 前序遍历:ABDEC * 1.首先遍历左子树,遍历到叶子结点为止 * @return * */ public boolean preorderTraverse(Node node) { //首先从根节点开始遍历 list.add(node); if (node.lChild != null) { // preorderTraverse(node.lChild); } if (node.rChild != null) { preorderTraverse(node.rChild); } return true; } /** * 中序遍历:DBEAC * @return * * */ public boolean inorderTarverse(Node node) { if (node.lChild != null) { inorderTarverse(node.lChild); } list.add(node); if (node.rChild != null) { inorderTarverse(node.rChild); } return true; } /** * 后序遍历:DEBCA * @return * * */ public boolean postorderTarverse(Node node) { if (node.lChild != null) { postorderTarverse(node.lChild); } if (node.rChild != null) { postorderTarverse(node.rChild); } list.add(node); return true; } public List<Node> getList() { return list; } @Test public void testGetDeth() { MyTree mt = new MyTree(); System.out.println("树的深度:" + getTreeDepth(mt.root)); //if(mt.preorderTraverse(mt.root)) System.out.print("前序遍历结果:"); //if(mt.inorderTarverse(mt.root)) System.out.print("中序遍历结果:"); if(mt.postorderTarverse(mt.root)) System.out.print("后序遍历结果:"); //if(mt.sequenceTraverse(mt.root)) System.out.print("层序遍历结果:"); for (Node node : mt.getList()) { System.out.print(node.data); } } }