顺序二叉树的满足条件:
1.一般指完全二叉树
2.第n个元素的左子树为2*n+1;
3.第n个元素的右子树为2*n+2;
4.第n个子树的父节点为(n-1)/2;
注意:n为数组下标所以是从0开始
代码实现:
package com.yg.tree;/*
@author Mu_Mu
@date 2020/3/4 10:50
顺序二叉树
*/
public class ArrBinaryTreeDemo {
public static void main(String[] args) {
int[] arr = {1, 2, 3, 4, 5, 6, 7};
ArrBinaryTree arrBinaryTree = new ArrBinaryTree(arr);
//arrBinaryTree.preOrder(0);
// arrBinaryTree.infixOrder(0);
arrBinaryTree.postOrder(0);
}
}
class ArrBinaryTree {
private int[] arr;
public ArrBinaryTree(int[] arr) {
this.arr = arr;
}
//前序遍历数组
/*
* @param index :数组下标
* @return : void
* @date : 2020/3/4 10:53
*/
public void preOrder(int index) {
if (arr == null && arr.length == 0) {
System.out.println("数组为空");
return;
}
System.out.println(arr[index]);
if ((index * 2 + 1) < arr.length) {
preOrder(index * 2 + 1);
}
if ((index * 2 + 2) < arr.length) {
preOrder(index * 2 + 2);
}
}
//中序遍历
public void infixOrder(int index) {
if (arr == null && arr.length == 0) {
System.out.println("数组为空");
return;
}
//先遍历左子树 (index*2+1)
if ((index * 2 + 1) < arr.length) {
infixOrder(index * 2 + 1);
}
if (index < arr.length) {
System.out.print(arr[index] + "\t");
}
if ((index * 2 + 2) < arr.length) {
infixOrder(index * 2 + 2);
}
}
//后序遍历
public void postOrder(int index) {
if (arr == null && arr.length == 0) {
System.out.println("数组为空");
return;
}
if ((index * 2 + 1) < arr.length) {
postOrder(index * 2 + 1);
}
if ((index * 2 + 2) < arr.length) {
postOrder(index * 2 + 2);
}
if (index < arr.length) {
System.out.println(arr[index]+"\t");
}
}
}