Merge branch 'youngyangyang04:master' into master

This commit is contained in:
Verolilo
2022-02-16 10:09:24 +08:00
committed by GitHub
5 changed files with 426 additions and 60 deletions

View File

@ -246,7 +246,35 @@ var levelOrder = function(root) {
```
TypeScript
```typescript
function levelOrder(root: TreeNode | null): number[][] {
let helperQueue: TreeNode[] = [];
let res: number[][] = [];
let tempArr: number[] = [];
if (root !== null) helperQueue.push(root);
let curNode: TreeNode;
while (helperQueue.length > 0) {
for (let i = 0, length = helperQueue.length; i < length; i++) {
curNode = helperQueue.shift()!;
tempArr.push(curNode.val);
if (curNode.left !== null) {
helperQueue.push(curNode.left);
}
if (curNode.right !== null) {
helperQueue.push(curNode.right);
}
}
res.push(tempArr);
tempArr = [];
}
return res;
};
```
Swift:
```swift
func levelOrder(_ root: TreeNode?) -> [[Int]] {
var res = [[Int]]()
@ -454,7 +482,31 @@ var levelOrderBottom = function(root) {
};
```
TypeScript:
```typescript
function levelOrderBottom(root: TreeNode | null): number[][] {
let helperQueue: TreeNode[] = [];
let resArr: number[][] = [];
let tempArr: number[] = [];
let tempNode: TreeNode;
if (root !== null) helperQueue.push(root);
while (helperQueue.length > 0) {
for (let i = 0, length = helperQueue.length; i < length; i++) {
tempNode = helperQueue.shift()!;
tempArr.push(tempNode.val);
if (tempNode.left !== null) helperQueue.push(tempNode.left);
if (tempNode.right !== null) helperQueue.push(tempNode.right);
}
resArr.push(tempArr);
tempArr = [];
}
return resArr.reverse();
};
```
Swift:
```swift
func levelOrderBottom(_ root: TreeNode?) -> [[Int]] {
var res = [[Int]]()
@ -657,7 +709,28 @@ var rightSideView = function(root) {
};
```
TypeScript
```typescript
function rightSideView(root: TreeNode | null): number[] {
let helperQueue: TreeNode[] = [];
let resArr: number[] = [];
let tempNode: TreeNode;
if (root !== null) helperQueue.push(root);
while (helperQueue.length > 0) {
for (let i = 0, length = helperQueue.length; i < length; i++) {
tempNode = helperQueue.shift()!;
if (i === length - 1) resArr.push(tempNode.val);
if (tempNode.left !== null) helperQueue.push(tempNode.left);
if (tempNode.right !== null) helperQueue.push(tempNode.right);
}
}
return resArr;
};
```
Swift:
```swift
func rightSideView(_ root: TreeNode?) -> [Int] {
var res = [Int]()
@ -868,7 +941,32 @@ var averageOfLevels = function(root) {
};
```
TypeScript
```typescript
function averageOfLevels(root: TreeNode | null): number[] {
let helperQueue: TreeNode[] = [];
let resArr: number[] = [];
let total: number = 0;
let tempNode: TreeNode;
if (root !== null) helperQueue.push(root);
while (helperQueue.length > 0) {
let length = helperQueue.length;
for (let i = 0; i < length; i++) {
tempNode = helperQueue.shift()!;
total += tempNode.val;
if (tempNode.left) helperQueue.push(tempNode.left);
if (tempNode.right) helperQueue.push(tempNode.right);
}
resArr.push(total / length);
total = 0;
}
return resArr;
};
```
Swift:
```swift
func averageOfLevels(_ root: TreeNode?) -> [Double] {
var res = [Double]()
@ -1092,7 +1190,30 @@ var levelOrder = function(root) {
};
```
TypeScript:
```typescript
function levelOrder(root: Node | null): number[][] {
let helperQueue: Node[] = [];
let resArr: number[][] = [];
let tempArr: number[] = [];
if (root !== null) helperQueue.push(root);
let curNode: Node;
while (helperQueue.length > 0) {
for (let i = 0, length = helperQueue.length; i < length; i++) {
curNode = helperQueue.shift()!;
tempArr.push(curNode.val);
helperQueue.push(...curNode.children);
}
resArr.push(tempArr);
tempArr = [];
}
return resArr;
};
```
Swift:
```swift
func levelOrder(_ root: Node?) -> [[Int]] {
var res = [[Int]]()
@ -1272,7 +1393,34 @@ var largestValues = function(root) {
};
```
TypeScript:
```typescript
function largestValues(root: TreeNode | null): number[] {
let helperQueue: TreeNode[] = [];
let resArr: number[] = [];
let tempNode: TreeNode;
let max: number = 0;
if (root !== null) helperQueue.push(root);
while (helperQueue.length > 0) {
for (let i = 0, length = helperQueue.length; i < length; i++) {
tempNode = helperQueue.shift()!;
if (i === 0) {
max = tempNode.val;
} else {
max = max > tempNode.val ? max : tempNode.val;
}
if (tempNode.left) helperQueue.push(tempNode.left);
if (tempNode.right) helperQueue.push(tempNode.right);
}
resArr.push(max);
}
return resArr;
};
```
Swift:
```swift
func largestValues(_ root: TreeNode?) -> [Int] {
var res = [Int]()
@ -1463,6 +1611,31 @@ var connect = function(root) {
};
```
TypeScript:
```typescript
function connect(root: Node | null): Node | null {
let helperQueue: Node[] = [];
let preNode: Node, curNode: Node;
if (root !== null) helperQueue.push(root);
while (helperQueue.length > 0) {
for (let i = 0, length = helperQueue.length; i < length; i++) {
if (i === 0) {
preNode = helperQueue.shift()!;
} else {
curNode = helperQueue.shift()!;
preNode.next = curNode;
preNode = curNode;
}
if (preNode.left) helperQueue.push(preNode.left);
if (preNode.right) helperQueue.push(preNode.right);
}
preNode.next = null;
}
return root;
};
```
go:
```GO
@ -1689,6 +1862,31 @@ var connect = function(root) {
return root;
};
```
TypeScript:
```typescript
function connect(root: Node | null): Node | null {
let helperQueue: Node[] = [];
let preNode: Node, curNode: Node;
if (root !== null) helperQueue.push(root);
while (helperQueue.length > 0) {
for (let i = 0, length = helperQueue.length; i < length; i++) {
if (i === 0) {
preNode = helperQueue.shift()!;
} else {
curNode = helperQueue.shift()!;
preNode.next = curNode;
preNode = curNode;
}
if (preNode.left) helperQueue.push(preNode.left);
if (preNode.right) helperQueue.push(preNode.right);
}
preNode.next = null;
}
return root;
};
```
go:
```GO
@ -1933,7 +2131,28 @@ var maxDepth = function(root) {
};
```
TypeScript:
```typescript
function maxDepth(root: TreeNode | null): number {
let helperQueue: TreeNode[] = [];
let resDepth: number = 0;
let tempNode: TreeNode;
if (root !== null) helperQueue.push(root);
while (helperQueue.length > 0) {
resDepth++;
for (let i = 0, length = helperQueue.length; i < length; i++) {
tempNode = helperQueue.shift()!;
if (tempNode.left) helperQueue.push(tempNode.left);
if (tempNode.right) helperQueue.push(tempNode.right);
}
}
return resDepth;
};
```
Swift:
```swift
func maxDepth(_ root: TreeNode?) -> Int {
guard let root = root else {
@ -2130,7 +2349,29 @@ var minDepth = function(root) {
};
```
TypeScript:
```typescript
function minDepth(root: TreeNode | null): number {
let helperQueue: TreeNode[] = [];
let resMin: number = 0;
let tempNode: TreeNode;
if (root !== null) helperQueue.push(root);
while (helperQueue.length > 0) {
resMin++;
for (let i = 0, length = helperQueue.length; i < length; i++) {
tempNode = helperQueue.shift()!;
if (tempNode.left === null && tempNode.right === null) return resMin;
if (tempNode.left !== null) helperQueue.push(tempNode.left);
if (tempNode.right !== null) helperQueue.push(tempNode.right);
}
}
return resMin;
};
```
Swift
```swift
func minDepth(_ root: TreeNode?) -> Int {
guard let root = root else {

View File

@ -531,82 +531,63 @@ class solution:
```go
//递归法
/**
* definition for a binary tree node.
* type treenode struct {
* val int
* left *treenode
* right *treenode
* Definition for a binary tree node.
* type TreeNode struct {
* Val int
* Left *TreeNode
* Right *TreeNode
* }
*/
func haspathsum(root *treenode, targetsum int) bool {
var flage bool //找没找到的标志
if root==nil{
return flage
func hasPathSum(root *TreeNode, targetSum int) bool {
if root == nil {
return false
}
pathsum(root,0,targetsum,&flage)
return flage
}
func pathsum(root *treenode, sum int,targetsum int,flage *bool){
sum+=root.val
if root.left==nil&&root.right==nil&&sum==targetsum{
*flage=true
return
}
if root.left!=nil&&!(*flage){//左节点不为空且还没找到
pathsum(root.left,sum,targetsum,flage)
}
if root.right!=nil&&!(*flage){//右节点不为空且没找到
pathsum(root.right,sum,targetsum,flage)
targetSum -= root.Val // 将targetSum在遍历每层的时候都减去本层节点的值
if root.Left == nil && root.Right == nil && targetSum == 0 { // 如果剩余的targetSum为0, 则正好就是符合的结果
return true
}
return hasPathSum(root.Left, targetSum) || hasPathSum(root.Right, targetSum) // 否则递归找
}
```
113 递归法
113. 路径总和 II
```go
/**
* definition for a binary tree node.
* type treenode struct {
* val int
* left *treenode
* right *treenode
* Definition for a binary tree node.
* type TreeNode struct {
* Val int
* Left *TreeNode
* Right *TreeNode
* }
*/
func pathsum(root *treenode, targetsum int) [][]int {
var result [][]int//最终结果
if root==nil{
return result
}
var sumnodes []int//经过路径的节点集合
haspathsum(root,&sumnodes,targetsum,&result)
func pathSum(root *TreeNode, targetSum int) [][]int {
result := make([][]int, 0)
traverse(root, &result, new([]int), targetSum)
return result
}
func haspathsum(root *treenode,sumnodes *[]int,targetsum int,result *[][]int){
*sumnodes=append(*sumnodes,root.val)
if root.left==nil&&root.right==nil{//叶子节点
fmt.println(*sumnodes)
var sum int
var number int
for k,v:=range *sumnodes{//求该路径节点的和
sum+=v
number=k
}
tempnodes:=make([]int,number+1)//新的nodes接受指针里的值防止最终指针里的值发生变动导致最后的结果都是最后一个sumnodes的值
for k,v:=range *sumnodes{
tempnodes[k]=v
}
if sum==targetsum{
*result=append(*result,tempnodes)
}
func traverse(node *TreeNode, result *[][]int, currPath *[]int, targetSum int) {
if node == nil { // 这个判空也可以挪到递归遍历左右子树时去判断
return
}
if root.left!=nil{
haspathsum(root.left,sumnodes,targetsum,result)
*sumnodes=(*sumnodes)[:len(*sumnodes)-1]//回溯
}
if root.right!=nil{
haspathsum(root.right,sumnodes,targetsum,result)
*sumnodes=(*sumnodes)[:len(*sumnodes)-1]//回溯
targetSum -= node.Val // 将targetSum在遍历每层的时候都减去本层节点的值
*currPath = append(*currPath, node.Val) // 把当前节点放到路径记录里
if node.Left == nil && node.Right == nil && targetSum == 0 { // 如果剩余的targetSum为0, 则正好就是符合的结果
// 不能直接将currPath放到result里面, 因为currPath是共享的, 每次遍历子树时都会被修改
pathCopy := make([]int, len(*currPath))
for i, element := range *currPath {
pathCopy[i] = element
}
*result = append(*result, pathCopy) // 将副本放到结果集里
}
traverse(node.Left, result, currPath, targetSum)
traverse(node.Right, result, currPath, targetSum)
*currPath = (*currPath)[:len(*currPath)-1] // 当前节点遍历完成, 从路径记录里删除掉
}
```

View File

@ -210,6 +210,45 @@ class Solution {
}
```
二维数组版本(易于理解):
```Java
class Solution {
public boolean canPartition(int[] nums) {
int sum = 0;
for (int i = 0; i < nums.length; i++) {
sum += nums[i];
}
if (sum % 2 == 1)
return false;
int target = sum / 2;
//dp[i][j]代表可装物品为0-i背包容量为j的情况下背包内容量的最大价值
int[][] dp = new int[nums.length][target + 1];
//初始化,dp[0][j]的最大价值nums[0](if j > weight[i])
//dp[i][0]均为0不用初始化
for (int j = nums[0]; j <= target; j++) {
dp[0][j] = nums[0];
}
//遍历物品,遍历背包
//递推公式:
for (int i = 1; i < nums.length; i++) {
for (int j = 0; j <= target; j++) {
//背包容量可以容纳nums[i]
if (j >= nums[i]) {
dp[i][j] = Math.max(dp[i - 1][j], dp[i - 1][j - nums[i]] + nums[i]);
} else {
dp[i][j] = dp[i - 1][j];
}
}
}
return dp[nums.length - 1][target] == target;
}
}
```
Python
```python
class Solution:

View File

@ -153,6 +153,8 @@ public:
Java
一维数组版本
```Java
class Solution {
public int lastStoneWeightII(int[] stones) {
@ -173,6 +175,41 @@ class Solution {
return sum - 2 * dp[target];
}
}
```
二维数组版本(便于理解)
```Java
class Solution {
public int lastStoneWeightII(int[] stones) {
int sum = 0;
for (int s : stones) {
sum += s;
}
int target = sum / 2;
//初始化dp[i][j]为可以放0-i物品背包容量为j的情况下背包中的最大价值
int[][] dp = new int[stones.length][target + 1];
//dp[i][0]默认初始化为0
//dp[0][j]取决于stones[0]
for (int j = stones[0]; j <= target; j++) {
dp[0][j] = stones[0];
}
for (int i = 1; i < stones.length; i++) {
for (int j = 1; j <= target; j++) {//注意是等于
if (j >= stones[i]) {
//不放:dp[i - 1][j] 放:dp[i - 1][j - stones[i]] + stones[i]
dp[i][j] = Math.max(dp[i - 1][j], dp[i - 1][j - stones[i]] + stones[i]);
} else {
dp[i][j] = dp[i - 1][j];
}
}
}
System.out.println(dp[stones.length - 1][target]);
return (sum - dp[stones.length - 1][target]) - dp[stones.length - 1][target];
}
}
```
Python

View File

@ -522,7 +522,75 @@ var postorderTraversal = function(root, res = []) {
```
TypeScript
```typescript
// 前序遍历(迭代法)
function preorderTraversal(root: TreeNode | null): number[] {
let helperStack: (TreeNode | null)[] = [];
let res: number[] = [];
let curNode: TreeNode | null;
if (root === null) return res;
helperStack.push(root);
while (helperStack.length > 0) {
curNode = helperStack.pop()!;
if (curNode !== null) {
if (curNode.right !== null) helperStack.push(curNode.right);
helperStack.push(curNode);
helperStack.push(null);
if (curNode.left !== null) helperStack.push(curNode.left);
} else {
curNode = helperStack.pop()!;
res.push(curNode.val);
}
}
return res;
};
// 中序遍历(迭代法)
function inorderTraversal(root: TreeNode | null): number[] {
let helperStack: (TreeNode | null)[] = [];
let res: number[] = [];
let curNode: TreeNode | null;
if (root === null) return res;
helperStack.push(root);
while (helperStack.length > 0) {
curNode = helperStack.pop()!;
if (curNode !== null) {
if (curNode.right !== null) helperStack.push(curNode.right);
helperStack.push(curNode);
helperStack.push(null);
if (curNode.left !== null) helperStack.push(curNode.left);
} else {
curNode = helperStack.pop()!;
res.push(curNode.val);
}
}
return res;
};
// 后序遍历(迭代法)
function postorderTraversal(root: TreeNode | null): number[] {
let helperStack: (TreeNode | null)[] = [];
let res: number[] = [];
let curNode: TreeNode | null;
if (root === null) return res;
helperStack.push(root);
while (helperStack.length > 0) {
curNode = helperStack.pop()!;
if (curNode !== null) {
if (curNode.right !== null) helperStack.push(curNode.right);
helperStack.push(curNode);
helperStack.push(null);
if (curNode.left !== null) helperStack.push(curNode.left);
} else {
curNode = helperStack.pop()!;
res.push(curNode.val);
}
}
return res;
};
```
-----------------------
<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>