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Merge branch 'youngyangyang04:master' into master

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Verolilo
2022-02-16 10:09:24 +08:00
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commit 2716470e63
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241
problems/0102.二叉树的层序遍历.md
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 {

101
problems/0112.路径总和.md
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
}
```

39
problems/0416.分割等和子集.md
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:

37
problems/1049.最后一块石头的重量II.md
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：

68
problems/二叉树的统一迭代法.md
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>