P23-二叉树遍历-前序-递归
2021-05-19 本文已影响0人
YonchanLew
//二叉树遍历
/*
* 前序遍历:根左右
* 中序遍历:左根右
* 后序遍历:左右根
* 层序遍历:从上往下、从左往右
*
* 递归遍历:使用递归方法遍历
* 迭代遍历:使用迭代方法实现递归函数,与递归等价
* morris遍历
* */
public class P23 {
/*
* 1
* / \
* 2 3
* / \
* 4 5
* / \
* 6 7
* */
public static void main(String[] args) {
TreeNode node7 = new TreeNode(7, null, null);
TreeNode node6 = new TreeNode(6, null, null);
TreeNode node5 = new TreeNode(5, node6, node7);
TreeNode node4 = new TreeNode(4, null, null);
TreeNode node3 = new TreeNode(3, null, null);
TreeNode node2 = new TreeNode(2, node4, node5);
TreeNode node1 = new TreeNode(1, node2, node3);
order(node1);
}
//前序-递归
//1-2-4-5-6-7-3
public static void order(TreeNode root){
if(root == null){
return;
}
System.out.println(root.val); //根
order(root.left); //左
order(root.right); //右
}
static class TreeNode{
int val;
TreeNode left;
TreeNode right;
int deep;
TreeNode(){}
TreeNode(int val){
this.val = val;
}
TreeNode(int val, TreeNode left, TreeNode right){
this.val = val;
this.left = left;
this.right = right;
}
}
}