二叉树基本操作

package java_study.JianZhiOffer;/** * Created by ethan on 2015/6/21. */public class TreeNode {    char value;    TreeNode lchild;    TreeNode rchild;    public TreeNode() {        this.value = 0;        this.lchild = null;        this.rchild = null;    }    public TreeNode(char value){        this.value = value;        this.lchild = null;        this.rchild = null;    }    public TreeNode(char value, TreeNode lchild, TreeNode rchild){        this.value = value;        this.lchild = lchild;        this.rchild = rchild;    }    public char getValue() {        return value;    }    public void setValue(char value) {        this.value = value;    }    public TreeNode getLchild() {        return lchild;    }    public void setLchild(TreeNode lchild) {        this.lchild = lchild;    }    public TreeNode getRchild() {        return rchild;    }    public void setRchild(TreeNode rchild) {        this.rchild = rchild;    }}package java_study.JianZhiOffer;import java.util.LinkedList;import java.util.Queue;import java.util.Stack;/** * Created by ethan on 2015/6/21. */public class TreeUtil {    // 接收前序和中序创建二叉树    public static TreeNode buildTree(String pre_str, int pre_start, int pre_end, String in_str, int in_start, int in_end){        if (pre_str==null || in_str==null) return null;        if (pre_start>pre_end || in_start>in_end) return null;        TreeNode root = new TreeNode(pre_str.charAt(pre_start));        int index_mid = in_start;        for (; index_mid<in_end; index_mid++)            if (in_str.charAt(index_mid) == pre_str.charAt(pre_start)) break;        if (index_mid > in_start)            root.setLchild(buildTree(pre_str, pre_start+1, pre_start+index_mid-in_start, in_str, in_start, index_mid-1));        if (index_mid < in_end)            root.setRchild(buildTree(pre_str, pre_start+index_mid-in_start+1, pre_end, in_str, index_mid+1, in_end));        return  root;    }        // 前序递归遍历    public static void preOrder(TreeNode root){        if (root != null){            System.out.print(root.getValue() + " ");            preOrder(root.getLchild());            preOrder(root.getRchild());        }    }    // 中序递归遍历    public static void inOrder(TreeNode root){        if (root != null ){            inOrder(root.getLchild());            System.out.print(root.getValue() + " ");            inOrder(root.getRchild());        }    }    // 后序递归遍历    public static void postOrder(TreeNode root){        if (root!=null){            postOrder(root.getLchild());            postOrder(root.getRchild());            System.out.print(root.getValue() + " ");        }    }    // 前序非递归遍历, 全压栈    public static void preOrderNoRecursive_1(TreeNode root){        if (root == null) return;        Stack<TreeNode> stack = new Stack<TreeNode>();        stack.push(root);        while (!stack.isEmpty()){            TreeNode tmp = stack.pop();            System.out.print(tmp.getValue() + " ");            if (tmp.getRchild()!=null){                stack.push(tmp.getRchild());            }            if (tmp.getLchild()!=null){                stack.push(tmp.getLchild());            }        }        System.out.println();    }    // 前序非递归遍历, 全压栈    public static void preOrderNoRecursive_2(TreeNode root){        if (root==null) return;        Stack<TreeNode> stack = new Stack<TreeNode>();        TreeNode tmp = root;        while (tmp!=null || !stack.isEmpty()){            while (tmp!=null){                System.out.print(tmp.value+" ");                stack.push(tmp);                tmp=tmp.getLchild();            }            if (!stack.isEmpty()){                tmp = stack.pop().getRchild();            }        }        System.out.println();    }    // 前序非递归遍历    public static void preOrderNoRecursive(TreeNode root){        if (root==null) return;        Stack<TreeNode> stack = new Stack<TreeNode>();        TreeNode tmp = root;        while (tmp!=null){            System.out.print(tmp.value+" ");            stack.push(tmp);            tmp=tmp.getLchild();        }        while (!stack.isEmpty()){            TreeNode top = stack.pop();            TreeNode tmp_1 = top.getRchild();            while (tmp_1!=null){                System.out.print(tmp_1.value+" ");                stack.push(tmp_1);                tmp_1=tmp_1.getLchild();            }        }        System.out.println();    }    // 中序非递归遍历    public static void inOrderNoRecursive_1(TreeNode root){        if (root==null) return;        Stack<TreeNode> stack = new Stack<TreeNode>();        TreeNode tmp = root;        while (tmp!=null || !stack.isEmpty()){            while (tmp!=null){                stack.push(tmp);                tmp = tmp.getLchild();            }            if (!stack.isEmpty()){                TreeNode myNode = stack.pop();                System.out.print(myNode.getValue()+" ");                tmp = myNode.getRchild();            }        }        System.out.println();    }    // 中序非递归遍历    public static void inOrderNoRecursive(TreeNode root){        if (root==null) return;        Stack<TreeNode> stack = new Stack<TreeNode>();        TreeNode tmp = root;        while (tmp!=null){            stack.push(tmp);            tmp = tmp.getLchild();        }        while (!stack.isEmpty()){            TreeNode top = stack.pop();            System.out.print(top.value + " ");            TreeNode tmp_1 = top.getRchild();            while (tmp_1!=null){                stack.push(tmp_1);                tmp_1=tmp_1.getLchild();            }        }        System.out.println();    }    // 后序非递归遍历    public static void postOrderNoRecursive(TreeNode root){        if (root==null) return;        TreeNode tmp = root;        TreeNode preVisited = null;        Stack<TreeNode> stack = new Stack<TreeNode>();        while (tmp!=null || !stack.isEmpty()){            while (tmp!=null){                stack.push(tmp);                tmp = tmp.getLchild();            }            tmp = stack.peek();            if (tmp.getRchild()==null || tmp.getRchild()==preVisited){                System.out.print(tmp.getValue()+ " ");                preVisited = tmp;                stack.pop();                tmp=null;            }else{                tmp = tmp.getRchild();            }        }        System.out.println();    }    // 层次遍历 利用队列    public static void levelTraverse(TreeNode root){        if (root == null) return;        Queue<TreeNode> stack = new LinkedList<TreeNode>();        stack.add(root);        while (!stack.isEmpty()){            TreeNode cur = stack.remove();            System.out.print(cur.getValue() + " ");            if (cur.getLchild()!=null)                stack.add(cur.getLchild());            if (cur.getRchild()!=null){                stack.add(cur.getRchild());            }        }        System.out.println();    }    // 二叉树的高度    public static int getDepth(TreeNode root){        if (root==null) return 0;        int depth_l = getDepth(root.getLchild());        int depth_r = getDepth(root.getRchild());        return (depth_l > depth_r ? depth_l : depth_r)+1;    }    // 二叉树的结点的个数    public static int countNodes(TreeNode root){        if (root==null) return 0;        return 1+countNodes(root.getLchild()) + countNodes(root.getRchild());    }}package java_study.JianZhiOffer;import org.junit.Test;/** * Created by ethan on 2015/6/21. */public class TestTreeUtil {    String pre_str = "abdhecfg";    String in_str = "hdbeafcg";    public TreeNode root = TreeUtil.buildTree(pre_str, 0, pre_str.length()-1, in_str, 0, in_str.length()-1);    // 手动初始化//    public TreeNode init(){//        TreeNode node0 = new TreeNode('a');//        TreeNode node1 = new TreeNode('b');//        TreeNode node2 = new TreeNode('c');//        TreeNode node3 = new TreeNode('d');//        TreeNode node4 = new TreeNode('e');//        TreeNode node5 = new TreeNode('f');//        TreeNode node6 = new TreeNode('g');//        TreeNode node7 = new TreeNode('h');//        node0.setLchild(node1);//        node0.setRchild(node2);//        node1.setLchild(node3);//        node1.setRchild(node4);//        node2.setLchild(node5);//        node2.setRchild(node6);//        node3.setLchild(node7);//        return node0;//    }    @Test    public void test3(){        System.out.println(TreeUtil.getDepth(root));        System.out.println(TreeUtil.countNodes(root));    }    @Test    public void test2(){        TreeUtil.preOrderNoRecursive(root);        TreeUtil.preOrderNoRecursive_1(root);        TreeUtil.preOrderNoRecursive_2(root);        TreeUtil.inOrderNoRecursive(root);        TreeUtil.inOrderNoRecursive_1(root);        TreeUtil.postOrderNoRecursive(root);        TreeUtil.levelTraverse(root);    }    @Test    public void test1(){        String pre_str = "abdhecfg";        String in_str = "hdbeafcg";        TreeNode root = TreeUtil.buildTree(pre_str, 0, pre_str.length()-1, in_str, 0, in_str.length()-1);        TreeUtil.postOrder(root);    }    @Test    public void test(){        TreeUtil.preOrder(root);        System.out.println();        TreeUtil.inOrder(root);        System.out.println();        TreeUtil.postOrder(root);        System.out.println();    }}