我要评论本文实例讲述了java实现的二叉树常用操作。分享给大家供大家参考，具体如下：
import java.util.arraydeque;
import java.util.queue;
import java.util.stack;
//二叉树的建树，前中后 递归非递归遍历 层序遍历
//node节点
class node {
int element;
node left;
node right;
public node() {
}
public node(int element) {
this.element = element;
}
}
// binarytree
public class tree {
// creat tree from array
public static node creattree(int[] data, int i) {
if (i >= data.length || data[i] == -1)
return null;
node temp = new node(data[i]);
temp.left = creattree(data, i * 2 + 1);
temp.right = creattree(data, i * 2 + 2);
return temp;
}
// pre前序遍历递归
public static void pre(node temp) {
if (temp == null)
return;
system.out.print(temp.element + " ");
pre(temp.left);
pre(temp.right);
}
// mid中序遍历递归
public static void mid(node temp) {
if (temp == null)
return;
mid(temp.left);
system.out.print(temp.element + " ");
mid(temp.right);
}
// last后序遍历递归
public static void last(node temp) {
if (temp == null)
return;
last(temp.left);
last(temp.right);
system.out.print(temp.element + " ");
}
// pre1前序遍历非递归
public static void pre1(node temp) {
stack<node> stack = new stack<>();
while (temp != null || !stack.isempty()) {
while (temp != null) {
stack.push(temp);
system.out.print(temp.element + " ");
temp = temp.left;
}
if (!stack.isempty()) {
temp = stack.pop().right;
}
}
}
// mid1中序遍历非递归
public static void mid1(node temp) {
stack<node> stack = new stack<>();
while (temp != null || !stack.isempty()) {
while (temp != null) {
stack.push(temp);
temp = temp.left;
}
if (!stack.isempty()) {
temp = stack.pop();
system.out.print(temp.element + " ");
temp = temp.right;
}
}
}
// last1后序遍历非递归
public static void last1(node temp) {
stack<node> stack = new stack<>();
stack<node> stack2 = new stack<>();
while (temp != null || !stack.isempty()) {
while (temp != null) {
stack.push(temp);
stack2.push(temp);
temp = temp.right;
}
if (!stack.isempty()) {
temp = stack.pop().left;
}
}
while (!stack2.isempty())
system.out.print(stack2.pop().element + " ");
}
// ceng层序遍历
public static void ceng(node temp) {
if (temp == null)
return;
queue<node> queue = new arraydeque<>();
queue.offer(temp);
while (!queue.isempty()) {
temp = queue.poll();
system.out.print(temp.element + " ");
if (temp.left != null)
queue.offer(temp.left);
if (temp.right != null)
queue.offer(temp.right);
}
}
// demo
public static void main(string[] args) {
int[] array = { 1, 2, 3, 4, 5, 6, 7, -1, -1, 10, -1, -1, 13 };
node tree = creattree(array, 0);
system.out.println("移动技术网测试结果：");
pre(tree);
system.out.println();
pre1(tree);
system.out.println();
mid(tree);
system.out.println();
mid1(tree);
system.out.println();
last(tree);
system.out.println();
last1(tree);
system.out.println();
ceng(tree);
}
}
运行结果：
更多关于java算法相关内容感兴趣的读者可查看本站专题：《java数据结构与算法教程》、《java操作dom节点技巧总结》、《java文件与目录操作技巧汇总》和《java缓存操作技巧汇总》
希望本文所述对大家java程序设计有所帮助。
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