开发公司官网_黄骅港信息吧_深圳广告公司_网易搜索引擎

一、前序遍历

144. Binary Tree Preorder Traversal

递归代码实现：

/*** Definition for a binary tree node.* struct TreeNode {*     int val;*     TreeNode *left;*     TreeNode *right;*     TreeNode() : val(0), left(nullptr), right(nullptr) {}*     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}*     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}* };*/
class Solution {
public:vector<int> preorderTraversal(TreeNode* root) {vector<int> preOrder;doPreOrderTraversal(root,preOrder);return preOrder;}void doPreOrderTraversal(TreeNode* root,vector<int> &preOrder){if(root){preOrder.push_back(root->val);doPreOrderTraversal(root->left,preOrder);doPreOrderTraversal(root->right,preOrder);}}
};

二、中序遍历

94. Binary Tree Inorder Traversal

递归代码实现

/*** Definition for a binary tree node.* struct TreeNode {*     int val;*     TreeNode *left;*     TreeNode *right;*     TreeNode() : val(0), left(nullptr), right(nullptr) {}*     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}*     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}* };*/
class Solution {
public:vector<int> inorderTraversal(TreeNode* root) {vector<int> inOrder;doInorderTraversal(root,inOrder);return inOrder;}void doInorderTraversal(TreeNode* root,vector<int> &inOrder){if(root){doInorderTraversal(root->left,inOrder);inOrder.push_back(root->val);doInorderTraversal(root->right,inOrder);}}
};

三、后续遍历

145. Binary Tree Postorder Traversal

后续代码实现

/*** Definition for a binary tree node.* struct TreeNode {*     int val;*     TreeNode *left;*     TreeNode *right;*     TreeNode() : val(0), left(nullptr), right(nullptr) {}*     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}*     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}* };*/
class Solution {
public:vector<int> postorderTraversal(TreeNode* root) {vector<int> postOrder;doPostOrderTraversal(root,postOrder);return postOrder;}void doPostOrderTraversal(TreeNode* root,vector<int> &postOrder){if(root){doPostOrderTraversal(root->left,postOrder);doPostOrderTraversal(root->right,postOrder);postOrder.push_back(root->val);}}
};