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GeezerVison is showing github.com — 二叉树遍历 · SinceraXY/Algorithm_code@777a96c

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  • .gitignore
  • leetcode/easy
    • 144_二叉树的前序遍历
      • 144_二叉树的前序遍历.cpp
      • 144_二叉树的前序遍历.go
      • 144_二叉树的前序遍历.py
      • README.md
    • 145_二叉树的后序遍历
      • 145_二叉树的后序遍历.cpp
      • 145_二叉树的后序遍历.go
      • 145_二叉树的后序遍历.py
      • README.md
    • 94_二叉树的中序遍历
      • 94_二叉树的中序遍历.cpp
      • 94_二叉树的中序遍历.go
      • 94_二叉树的中序遍历.py
      • README.md
  • notes
    • README.md
    • topics
      • 二叉树算法专题.md
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‎.gitignore‎

Copy file name to clipboardExpand all lines: .gitignore
+1Lines changed: 1 addition & 0 deletions
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@@ -3,6 +3,7 @@
33
Thumbs.db
44
.idea/
55
.vscode/
6+
.kiro/
67
*.code-workspace
78

89
# Python
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‎leetcode/easy/144_二叉树的前序遍历/144_二叉树的前序遍历.cpp‎

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+92Lines changed: 92 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,92 @@
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/**
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* Definition for a binary tree node.
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* struct TreeNode {
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* int val;
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* TreeNode *left;
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* TreeNode *right;
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* TreeNode() : val(0), left(nullptr), right(nullptr) {}
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* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
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* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
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* };
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*/
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//递归
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class Solution {
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public:
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void preorder(TreeNode *root, vector<int> &res) {
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if(root==nullptr){
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return;
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}
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res.push_back(root->val);
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preorder(root->left, res);
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preorder(root->right,res);
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}
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vector<int> preorderTraversal(TreeNode* root) {
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vector<int> res;
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preorder(root, res);
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return res;
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}
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};
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//迭代
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class Solution {
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public:
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vector<int> preorderTraversal(TreeNode* root) {
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vector<int> res;
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if(root == nullptr){
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return res;
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}
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stack<TreeNode*> stk;
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TreeNode* node = root;
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while(!stk.empty()||node!=nullptr) {
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while(node!=nullptr) {
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res.emplace_back(node->val);
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stk.emplace(node);
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node=node->left;
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}
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node=stk.top();
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stk.pop();
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node=node->right;
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}
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return res;
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}
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};
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//Morris遍历
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class Solution {
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public:
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vector<int> preorderTraversal(TreeNode *root) {
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vector<int> res;
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if (root == nullptr) {
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return res;
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}
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TreeNode *p1 = root, *p2 = nullptr;
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while (p1 != nullptr) {
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p2 = p1->left;
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if (p2 != nullptr) {
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while (p2->right != nullptr && p2->right != p1) {
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p2 = p2->right;
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}
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if (p2->right == nullptr) {
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res.emplace_back(p1->val);
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p2->right = p1;
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p1 = p1->left;
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continue;
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} else {
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p2->right = nullptr;
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}
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} else {
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res.emplace_back(p1->val);
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}
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p1 = p1->right;
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}
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return res;
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}
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};
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‎leetcode/easy/144_二叉树的前序遍历/144_二叉树的前序遍历.go‎

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+70Lines changed: 70 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,70 @@
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/**
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* Definition for a binary tree node.
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* type TreeNode struct {
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* Val int
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* Left *TreeNode
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* Right *TreeNode
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* }
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*/
9+
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//递归
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func preorderTraversal(root *TreeNode) []int {
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vals := []int{}
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var preorder func(*TreeNode)
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preorder = func(node *TreeNode) {
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if node == nil {
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return
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}
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vals = append(vals, node.Val)
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preorder(node.Left)
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preorder(node.Right)
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}
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preorder(root)
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return vals
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}
25+
26+
27+
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//迭代
29+
func preorderTraversal(root *TreeNode) []int {
30+
vals := []int{}
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stack := []*TreeNode{}
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node := root
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for node != nil || len(stack) > 0 {
34+
for node != nil {
35+
vals = append(vals, node.Val)
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stack = append(stack, node)
37+
node = node.Left
38+
}
39+
node = stack[len(stack)-1].Right
40+
stack = stack[:len(stack)-1]
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}
42+
return vals
43+
}
44+
45+
46+
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//Morris遍历
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func preorderTraversal(root *TreeNode) []int {
49+
vals := []int{}
50+
var p1, p2 *TreeNode = root, nil
51+
for p1 != nil {
52+
p2 = p1.Left
53+
if p2 != nil {
54+
for p2.Right != nil && p2.Right != p1 {
55+
p2 = p2.Right
56+
}
57+
if p2.Right == nil {
58+
vals = append(vals, p1.Val)
59+
p2.Right = p1
60+
p1 = p1.Left
61+
continue
62+
}
63+
p2.Right = nil
64+
} else {
65+
vals = append(vals, p1.Val)
66+
}
67+
p1 = p1.Right
68+
}
69+
return vals
70+
}
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‎leetcode/easy/144_二叉树的前序遍历/144_二叉树的前序遍历.py‎

Copy file name to clipboard
+68Lines changed: 68 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,68 @@
1+
# Definition for a binary tree node.
2+
# class TreeNode:
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# def __init__(self, val=0, left=None, right=None):
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# self.val = val
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# self.left = left
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# self.right = right
7+
8+
#递归
9+
class Solution:
10+
def preorderTraversal(self, root: Optional[TreeNode]) -> List[int]:
11+
def preorder(root: TreeNode):
12+
if not root:
13+
return
14+
res.append(root.val)
15+
preorder(root.left)
16+
preorder(root.right)
17+
18+
res = list()
19+
preorder(root)
20+
return res
21+
22+
23+
24+
#迭代
25+
class Solution:
26+
def preorderTraversal(self, root: Optional[TreeNode]) -> List[int]:
27+
res = list()
28+
if not root:
29+
return res
30+
31+
stack = []
32+
node = root
33+
while stack or node:
34+
while node:
35+
res.append(node.val)
36+
stack.append(node)
37+
node = node.left
38+
node = stack.pop()
39+
node = node.right
40+
return res
41+
42+
43+
44+
#Morris遍历
45+
class Solution:
46+
def preorderTraversal(self, root: Optional[TreeNode]) -> List[int]:
47+
res = list()
48+
if not root:
49+
return res
50+
51+
p1 = root
52+
while p1:
53+
p2 = p1.left
54+
if p2:
55+
while p2.right and p2.right != p1:
56+
p2 = p2.right
57+
if not p2.right:
58+
res.append(p1.val)
59+
p2.right = p1
60+
p1 = p1.left
61+
continue
62+
else:
63+
p2.right = None
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else:
65+
res.append(p1.val)
66+
p1 = p1.right
67+
68+
return res

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