学校网站建设项目管理报告,wordpress 阿里云,如何通过轻淘客做网站,简约创意网页设计提示#xff1a;文章写完后#xff0c;目录可以自动生成#xff0c;如何生成可参考右边的帮助文档 文章目录 前言一、力扣144. 二叉树的前序遍历二、力扣145. 二叉树的后序遍历三、力扣94. 二叉树的中序遍历四、力扣144. 二叉树的前序遍历无、力扣145. 二叉树的后序遍历六、… 提示文章写完后目录可以自动生成如何生成可参考右边的帮助文档 文章目录 前言一、力扣144. 二叉树的前序遍历二、力扣145. 二叉树的后序遍历三、力扣94. 二叉树的中序遍历四、力扣144. 二叉树的前序遍历无、力扣145. 二叉树的后序遍历六、力扣94. 二叉树的中序遍历 前言
—二叉树的前中后序遍历使用递归个迭代两种方法
一、力扣144. 二叉树的前序遍历
/*** Definition for a binary tree node.* public class TreeNode {* int val;* TreeNode left;* TreeNode right;* TreeNode() {}* TreeNode(int val) { this.val val; }* TreeNode(int val, TreeNode left, TreeNode right) {* this.val val;* this.left left;* this.right right;* }* }*/
class Solution {public ListInteger preorderTraversal(TreeNode root) {ListInteger res new ArrayList();fun(res,root);return res;}public void fun(ListInteger list, TreeNode root){if(root null){return ;}list.add(root.val);fun(list,root.left);fun(list,root.right);}
}二、力扣145. 二叉树的后序遍历
在这里插入代码片/*** Definition for a binary tree node.* public class TreeNode {* int val;* TreeNode left;* TreeNode right;* TreeNode() {}* TreeNode(int val) { this.val val; }* TreeNode(int val, TreeNode left, TreeNode right) {* this.val val;* this.left left;* this.right right;* }* }*/
class Solution {public ListInteger postorderTraversal(TreeNode root) {ListInteger res new ArrayList();fun(res,root);return res;}public void fun(ListInteger res,TreeNode root){if(root null){return;}fun(res,root.left);fun(res,root.right);res.add(root.val);}
}三、力扣94. 二叉树的中序遍历
/*** Definition for a binary tree node.* public class TreeNode {* int val;* TreeNode left;* TreeNode right;* TreeNode() {}* TreeNode(int val) { this.val val; }* TreeNode(int val, TreeNode left, TreeNode right) {* this.val val;* this.left left;* this.right right;* }* }*/
class Solution {public ListInteger inorderTraversal(TreeNode root) {ListInteger res new ArrayList();fun(res,root);return res;}public void fun(ListInteger res , TreeNode root){if(root null){return;}fun(res,root.left);res.add(root.val);fun(res,root.right);}
}四、力扣144. 二叉树的前序遍历
/*** Definition for a binary tree node.* public class TreeNode {* int val;* TreeNode left;* TreeNode right;* TreeNode() {}* TreeNode(int val) { this.val val; }* TreeNode(int val, TreeNode left, TreeNode right) {* this.val val;* this.left left;* this.right right;* }* }*/
class Solution {public ListInteger preorderTraversal(TreeNode root) {DequeTreeNode deq new LinkedList();ListInteger res new ArrayList();if(root null){return res;}deq.offerLast(root);while(!deq.isEmpty()){TreeNode p deq.pollLast();res.add(p.val);if(p.right ! null){deq.offerLast(p.right);}if(p.left ! null){deq.offerLast(p.left);}}return res;}
}无、力扣145. 二叉树的后序遍历
/*** Definition for a binary tree node.* public class TreeNode {* int val;* TreeNode left;* TreeNode right;* TreeNode() {}* TreeNode(int val) { this.val val; }* TreeNode(int val, TreeNode left, TreeNode right) {* this.val val;* this.left left;* this.right right;* }* }*/
class Solution {public ListInteger postorderTraversal(TreeNode root) {DequeTreeNode deq new LinkedList();ListInteger res new LinkedList();if(root null){return res;}deq.offerLast(root);while(!deq.isEmpty()){TreeNode p deq.pollLast();res.add(p.val);if(p.left ! null){deq.offerLast(p.left);}if(p.right ! null){deq.offerLast(p.right);}}Collections.reverse(res);return res;}
}六、力扣94. 二叉树的中序遍历
/*** Definition for a binary tree node.* public class TreeNode {* int val;* TreeNode left;* TreeNode right;* TreeNode() {}* TreeNode(int val) { this.val val; }* TreeNode(int val, TreeNode left, TreeNode right) {* this.val val;* this.left left;* this.right right;* }* }*/
class Solution {public ListInteger inorderTraversal(TreeNode root) {DequeTreeNode deq new LinkedList();ListInteger res new LinkedList();if(root null){return res;}TreeNode p root;while(!deq.isEmpty() || p ! null){if(p ! null){deq.offerLast(p);p p.left;}else{p deq.pollLast();res.add(p.val);p p.right;}}return res;}
}
