Merge branch 'master' of github.com:youngyangyang04/leetcode-master

This commit is contained in:
programmercarl
2022-04-26 11:04:51 +08:00
22 changed files with 685 additions and 53 deletions

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@ -439,6 +439,55 @@ var solveSudoku = function(board) {
};
```
### TypeScript
```typescript
/**
Do not return anything, modify board in-place instead.
*/
function isValid(col: number, row: number, val: string, board: string[][]): boolean {
let n: number = board.length;
// 列向检查
for (let rowIndex = 0; rowIndex < n; rowIndex++) {
if (board[rowIndex][col] === val) return false;
}
// 横向检查
for (let colIndex = 0; colIndex < n; colIndex++) {
if (board[row][colIndex] === val) return false;
}
// 九宫格检查
const startX = Math.floor(col / 3) * 3;
const startY = Math.floor(row / 3) * 3;
for (let rowIndex = startY; rowIndex < startY + 3; rowIndex++) {
for (let colIndex = startX; colIndex < startX + 3; colIndex++) {
if (board[rowIndex][colIndex] === val) return false;
}
}
return true;
}
function solveSudoku(board: string[][]): void {
let n: number = 9;
backTracking(n, board);
function backTracking(n: number, board: string[][]): boolean {
for (let row = 0; row < n; row++) {
for (let col = 0; col < n; col++) {
if (board[row][col] === '.') {
for (let i = 1; i <= n; i++) {
if (isValid(col, row, String(i), board)) {
board[row][col] = String(i);
if (backTracking(n, board) === true) return true;
board[row][col] = '.';
}
}
return false;
}
}
}
return true;
}
};
```
### C
```C

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@ -331,6 +331,34 @@ var permute = function(nums) {
```
## TypeScript
```typescript
function permute(nums: number[]): number[][] {
const resArr: number[][] = [];
const helperSet: Set<number> = new Set();
backTracking(nums, []);
return resArr;
function backTracking(nums: number[], route: number[]): void {
if (route.length === nums.length) {
resArr.push(route.slice());
return;
}
let tempVal: number;
for (let i = 0, length = nums.length; i < length; i++) {
tempVal = nums[i];
if (!helperSet.has(tempVal)) {
route.push(tempVal);
helperSet.add(tempVal);
backTracking(nums, route);
route.pop();
helperSet.delete(tempVal);
}
}
}
};
```
### C
```c

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@ -292,6 +292,34 @@ var permuteUnique = function (nums) {
```
### TypeScript
```typescript
function permuteUnique(nums: number[]): number[][] {
nums.sort((a, b) => a - b);
const resArr: number[][] = [];
const usedArr: boolean[] = new Array(nums.length).fill(false);
backTracking(nums, []);
return resArr;
function backTracking(nums: number[], route: number[]): void {
if (route.length === nums.length) {
resArr.push(route.slice());
return;
}
for (let i = 0, length = nums.length; i < length; i++) {
if (i > 0 && nums[i] === nums[i - 1] && usedArr[i - 1] === false) continue;
if (usedArr[i] === false) {
route.push(nums[i]);
usedArr[i] = true;
backTracking(nums, route);
usedArr[i] = false;
route.pop();
}
}
}
};
```
### Swift
```swift

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@ -457,6 +457,58 @@ var solveNQueens = function(n) {
};
```
## TypeScript
```typescript
function solveNQueens(n: number): string[][] {
const board: string[][] = new Array(n).fill(0).map(_ => new Array(n).fill('.'));
const resArr: string[][] = [];
backTracking(n, 0, board);
return resArr;
function backTracking(n: number, rowNum: number, board: string[][]): void {
if (rowNum === n) {
resArr.push(transformBoard(board));
return;
}
for (let i = 0; i < n; i++) {
if (isValid(i, rowNum, board) === true) {
board[rowNum][i] = 'Q';
backTracking(n, rowNum + 1, board);
board[rowNum][i] = '.';
}
}
}
};
function isValid(col: number, row: number, board: string[][]): boolean {
const n: number = board.length;
if (col < 0 || col >= n || row < 0 || row >= n) return false;
// 检查列
for (let row of board) {
if (row[col] === 'Q') return false;
}
// 检查45度方向
let x: number = col,
y: number = row;
while (y >= 0 && x < n) {
if (board[y--][x++] === 'Q') return false;
}
// 检查135度方向
x = col;
y = row;
while (x >= 0 && y >= 0) {
if (board[y--][x--] === 'Q') return false;
}
return true;
}
function transformBoard(board: string[][]): string[] {
const resArr = [];
for (let row of board) {
resArr.push(row.join(''));
}
return resArr;
}
```
### Swift
```swift

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@ -211,7 +211,7 @@ func maxSubArray(nums []int) int {
return maxSum
}
```
### Javascript:
```Javascript
var maxSubArray = function(nums) {
@ -230,6 +230,41 @@ var maxSubArray = function(nums) {
};
```
### TypeScript
**贪心**
```typescript
function maxSubArray(nums: number[]): number {
let curSum: number = 0;
let resMax: number = -Infinity;
for (let i = 0, length = nums.length; i < length; i++) {
curSum += nums[i];
resMax = Math.max(curSum, resMax);
if (curSum < 0) curSum = 0;
}
return resMax;
};
```
**动态规划**
```typescript
// 动态规划
function maxSubArray(nums: number[]): number {
const length = nums.length;
if (length === 0) return 0;
const dp: number[] = [];
dp[0] = nums[0];
let resMax: number = nums[0];
for (let i = 1; i < length; i++) {
dp[i] = Math.max(dp[i - 1] + nums[i], nums[i]);
resMax = Math.max(resMax, dp[i]);
}
return resMax;
};
```
-----------------------

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@ -408,7 +408,28 @@ class Solution:
return True
```
## Go
```python
# 遵循Carl的写法只添加了节点判断的部分
class Solution:
def isValidBST(self, root: TreeNode) -> bool:
# method 2
que, pre = [], None
while root or que:
while root:
que.append(root)
root = root.left
root = que.pop()
# 对第一个节点只做记录,对后面的节点进行比较
if pre is None:
pre = root.val
else:
if pre >= root.val: return False
pre = root.val
root = root.right
return True
```
## Go
```Go
import "math"

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@ -437,41 +437,6 @@ class Solution:
return True
```
层序遍历
```python
class Solution:
def isSymmetric(self, root: TreeNode) -> bool:
if not root: return True
que, cnt = [[root.left, root.right]], 1
while que:
nodes, tmp, sign = que.pop(), [], False
for node in nodes:
if not node:
tmp.append(None)
tmp.append(None)
else:
if node.left:
tmp.append(node.left)
sign = True
else:
tmp.append(None)
if node.right:
tmp.append(node.right)
sign = True
else:
tmp.append(None)
p1, p2 = 0, len(nodes) - 1
while p1 < p2:
if (not nodes[p1] and nodes[p2]) or (nodes[p1] and not nodes[p2]): return False
elif nodes[p1] and nodes[p2] and nodes[p1].val != nodes[p2].val: return False
p1 += 1
p2 -= 1
if sign: que.append(tmp)
cnt += 1
return True
```
## Go
```go

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@ -790,7 +790,7 @@ func findRootIndex(target int,inorder []int) int{
```javascript
var buildTree = function(inorder, postorder) {
if (!preorder.length) return null;
if (!inorder.length) return null;
const rootVal = postorder.pop(); // 从后序遍历的数组中获取中间节点的值, 即数组最后一个值
let rootIndex = inorder.indexOf(rootVal); // 获取中间节点在中序遍历中的下标
const root = new TreeNode(rootVal); // 创建中间节点

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@ -355,6 +355,7 @@ func sortedArrayToBST(nums []int) *TreeNode {
```
## JavaScript
递归
```javascript
var sortedArrayToBST = function (nums) {
@ -372,7 +373,44 @@ var sortedArrayToBST = function (nums) {
return buildTree(nums, 0, nums.length - 1);
};
```
迭代
```JavaScript
var sortedArrayToBST = function(nums) {
if(nums.length===0){
return null;
}
let root=new TreeNode(0); //初始根节点
let nodeQue=[root]; //放遍历的节点,并初始化
let leftQue=[0]; //放左区间的下标,初始化
let rightQue=[nums.length-1]; // 放右区间的下标
while(nodeQue.length){
let curNode=nodeQue.pop();
let left=leftQue.pop();
let right=rightQue.pop();
let mid=left+Math.floor((right-left)/2);
curNode.val=nums[mid]; //将下标为mid的元素给中间节点
// 处理左区间
if(left<=mid-1){
curNode.left=new TreeNode(0);
nodeQue.push(curNode.left);
leftQue.push(left);
rightQue.push(mid-1);
}
// 处理右区间
if(right>=mid+1){
curNode.right=new TreeNode(0);
nodeQue.push(curNode.right);
leftQue.push(mid+1);
rightQue.push(right);
}
}
return root;
};
```
## TypeScript
```typescript

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@ -40,7 +40,7 @@
本题首先要清楚两点:
* 只有一只股票!
* 当前只有买股票或者股票的操作
* 当前只有买股票或者股票的操作
想获得利润至少要两天为一个交易单元。

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@ -315,5 +315,75 @@ class Solution {
}
```
C:
```C
typedef struct HashNodeTag {
int key; /* num */
struct HashNodeTag *next;
}HashNode;
/* Calcualte the hash key */
static inline int hash(int key, int size) {
int index = key % size;
return (index > 0) ? (index) : (-index);
}
/* Calculate the sum of the squares of its digits*/
static inline int calcSquareSum(int num) {
unsigned int sum = 0;
while(num > 0) {
sum += (num % 10) * (num % 10);
num = num/10;
}
return sum;
}
#define HASH_TABLE_SIZE (32)
bool isHappy(int n){
int sum = n;
int index = 0;
bool bHappy = false;
bool bExit = false;
/* allocate the memory for hash table with chaining method*/
HashNode ** hashTable = (HashNode **)calloc(HASH_TABLE_SIZE, sizeof(HashNode));
while(bExit == false) {
/* check if n has been calculated */
index = hash(n, HASH_TABLE_SIZE);
HashNode ** p = hashTable + index;
while((*p) && (bExit == false)) {
/* Check if this num was calculated, if yes, this will be endless loop */
if((*p)->key == n) {
bHappy = false;
bExit = true;
}
/* move to next node of the same index */
p = &((*p)->next);
}
/* put n intot hash table */
HashNode * newNode = (HashNode *)malloc(sizeof(HashNode));
newNode->key = n;
newNode->next = NULL;
*p = newNode;
sum = calcSquareSum(n);
if(sum == 1) {
bHappy = true;
bExit = true;
}
else {
n = sum;
}
}
return bHappy;
}
```
-----------------------
<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

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@ -275,15 +275,11 @@ func (this *MyQueue) Pop() int {
/** Get the front element. */
func (this *MyQueue) Peek() int {
for len(this.stack) != 0 {
val := this.stack[len(this.stack)-1]
this.stack = this.stack[:len(this.stack)-1]
this.back = append(this.back, val)
}
if len(this.back) == 0 {
val := this.Pop()
if val == 0 {
return 0
}
val := this.back[len(this.back)-1]
this.back = append(this.back, val)
return val
}

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@ -506,6 +506,50 @@ var findItinerary = function(tickets) {
```
### TypeScript
```typescript
function findItinerary(tickets: string[][]): string[] {
/**
TicketsMap 实例:
{ NRT: Map(1) { 'JFK' => 1 }, JFK: Map(2) { 'KUL' => 1, 'NRT' => 1 } }
这里选择Map数据结构的原因是与Object类型的一个主要差异是Map实例会维护键值对的插入顺序。
*/
type TicketsMap = {
[index: string]: Map<string, number>
};
tickets.sort((a, b) => {
return a[1] < b[1] ? -1 : 1;
});
const ticketMap: TicketsMap = {};
for (const [from, to] of tickets) {
if (ticketMap[from] === undefined) {
ticketMap[from] = new Map();
}
ticketMap[from].set(to, (ticketMap[from].get(to) || 0) + 1);
}
const resRoute = ['JFK'];
backTracking(tickets.length, ticketMap, resRoute);
return resRoute;
function backTracking(ticketNum: number, ticketMap: TicketsMap, route: string[]): boolean {
if (route.length === ticketNum + 1) return true;
const targetMap = ticketMap[route[route.length - 1]];
if (targetMap !== undefined) {
for (const [to, count] of targetMap.entries()) {
if (count > 0) {
route.push(to);
targetMap.set(to, count - 1);
if (backTracking(ticketNum, ticketMap, route) === true) return true;
targetMap.set(to, count);
route.pop();
}
}
}
return false;
}
};
```
### Swift
直接迭代tickets数组

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@ -281,6 +281,38 @@ impl Solution {
}
}
```
C:
```C
int* intersection1(int* nums1, int nums1Size, int* nums2, int nums2Size, int* returnSize){
int nums1Cnt[1000] = {0};
int lessSize = nums1Size < nums2Size ? nums1Size : nums2Size;
int * result = (int *) calloc(lessSize, sizeof(int));
int resultIndex = 0;
int* tempNums;
int i;
/* Calculate the number's counts for nums1 array */
for(i = 0; i < nums1Size; i ++) {
nums1Cnt[nums1[i]]++;
}
/* Check if the value in nums2 is existing in nums1 count array */
for(i = 0; i < nums2Size; i ++) {
if(nums1Cnt[nums2[i]] > 0) {
result[resultIndex] = nums2[i];
resultIndex ++;
/* Clear this count to avoid duplicated value */
nums1Cnt[nums2[i]] = 0;
}
}
* returnSize = resultIndex;
return result;
}
```
## 相关题目
* 350.两个数组的交集 II

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@ -298,5 +298,55 @@ var wiggleMaxLength = function(nums) {
};
```
### TypeScript
**贪心**
```typescript
function wiggleMaxLength(nums: number[]): number {
let length: number = nums.length;
if (length <= 1) return length;
let preDiff: number = 0;
let curDiff: number = 0;
let count: number = 1;
for (let i = 1; i < length; i++) {
curDiff = nums[i] - nums[i - 1];
if (
(preDiff <= 0 && curDiff > 0) ||
(preDiff >= 0 && curDiff < 0)
) {
preDiff = curDiff;
count++;
}
}
return count;
};
```
**动态规划**
```typescript
function wiggleMaxLength(nums: number[]): number {
const length: number = nums.length;
if (length <= 1) return length;
const dp: number[][] = new Array(length).fill(0).map(_ => []);
dp[0][0] = 1; // 第一个数作为波峰
dp[0][1] = 1; // 第一个数作为波谷
for (let i = 1; i < length; i++) {
dp[i][0] = 1;
dp[i][1] = 1;
for (let j = 0; j < i; j++) {
if (nums[j] < nums[i]) dp[i][0] = Math.max(dp[i][0], dp[j][1] + 1);
}
for (let j = 0; j < i; j++) {
if (nums[j] > nums[i]) dp[i][1] = Math.max(dp[i][1], dp[j][0] + 1);
}
}
return Math.max(dp[length - 1][0], dp[length - 1][1]);
};
```
-----------------------
<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

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@ -209,7 +209,50 @@ var findContentChildren = function(g, s) {
```
### TypeScript
```typescript
// 大饼干尽量喂胃口大的
function findContentChildren(g: number[], s: number[]): number {
g.sort((a, b) => a - b);
s.sort((a, b) => a - b);
const childLength: number = g.length,
cookieLength: number = s.length;
let curChild: number = childLength - 1,
curCookie: number = cookieLength - 1;
let resCount: number = 0;
while (curChild >= 0 && curCookie >= 0) {
if (g[curChild] <= s[curCookie]) {
curCookie--;
resCount++;
}
curChild--;
}
return resCount;
};
```
```typescript
// 小饼干先喂饱小胃口的
function findContentChildren(g: number[], s: number[]): number {
g.sort((a, b) => a - b);
s.sort((a, b) => a - b);
const childLength: number = g.length,
cookieLength: number = s.length;
let curChild: number = 0,
curCookie: number = 0;
while (curChild < childLength && curCookie < cookieLength) {
if (g[curChild] <= s[curCookie]) {
curChild++;
}
curCookie++;
}
return curChild;
};
```
### C
```c
int cmp(int* a, int* b) {
return *a - *b;

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@ -396,7 +396,35 @@ var findSubsequences = function(nums) {
```
## TypeScript
```typescript
function findSubsequences(nums: number[]): number[][] {
const resArr: number[][] = [];
backTracking(nums, 0, []);
return resArr;
function backTracking(nums: number[], startIndex: number, route: number[]): void {
let length: number = nums.length;
if (route.length >= 2) {
resArr.push(route.slice());
}
const usedSet: Set<number> = new Set();
for (let i = startIndex; i < length; i++) {
if (
nums[i] < route[route.length - 1] ||
usedSet.has(nums[i])
) continue;
usedSet.add(nums[i]);
route.push(nums[i]);
backTracking(nums, i + 1, route);
route.pop();
}
}
};
```
### C
```c
int* path;
int pathTop;

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@ -276,7 +276,7 @@ func search(nums []int, target int) int {
```
**JavaScript:**
(版本一)左闭右闭区间
(版本一)左闭右闭区间 [left, right]
```js
/**
@ -285,10 +285,12 @@ func search(nums []int, target int) int {
* @return {number}
*/
var search = function(nums, target) {
// right是数组最后一个数的下标num[right]在查找范围内,是左闭右闭区间
let left = 0, right = nums.length - 1;
// 使用左闭右闭区间
// 当left=right时由于nums[right]在查找范围内,所以要包括此情况
while (left <= right) {
let mid = left + Math.floor((right - left)/2);
// 如果中间数大于目标值要把中间数排除查找范围所以右边界更新为mid-1如果右边界更新为mid那中间数还在下次查找范围内
if (nums[mid] > target) {
right = mid - 1; // 去左面闭区间寻找
} else if (nums[mid] < target) {
@ -300,7 +302,7 @@ var search = function(nums, target) {
return -1;
};
```
(版本二)左闭右开区间
(版本二)左闭右开区间 [left, right)
```js
/**
@ -309,10 +311,13 @@ var search = function(nums, target) {
* @return {number}
*/
var search = function(nums, target) {
let left = 0, right = nums.length;
// 使用左闭右开区间 [left, right)
// right是数组最后一个数的下标+1nums[right]不在查找范围内,是左闭右开区间
let left = 0, right = nums.length;
// 当left=right时由于nums[right]不在查找范围,所以不必包括此情况
while (left < right) {
let mid = left + Math.floor((right - left)/2);
// 如果中间值大于目标值,中间值不应在下次查找的范围内,但中间值的前一个值应在;
// 由于right本来就不在查找范围内所以将右边界更新为中间值如果更新右边界为mid-1则将中间值的前一个值也踢出了下次寻找范围
if (nums[mid] > target) {
right = mid; // 去左区间寻找
} else if (nums[mid] < target) {

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@ -220,6 +220,73 @@ int main() {
## Go
```Go
package main
import "fmt"
type TreeNode struct {
Val int
Left *TreeNode
Right *TreeNode
}
func constructBinaryTree(array []int) *TreeNode {
var root *TreeNode
nodes := make([]*TreeNode, len(array))
// 初始化二叉树节点
for i := 0; i < len(nodes); i++ {
var node *TreeNode
if array[i] != -1 {
node = &TreeNode{Val: array[i]}
}
nodes[i] = node
if i == 0 {
root = node
}
}
// 串联节点
for i := 0; i*2+2 < len(array); i++ {
if nodes[i] != nil {
nodes[i].Left = nodes[i*2+1]
nodes[i].Right = nodes[i*2+2]
}
}
return root
}
func printBinaryTree(root *TreeNode, n int) {
var queue []*TreeNode
if root != nil {
queue = append(queue, root)
}
result := []int{}
for len(queue) > 0 {
for j := 0; j < len(queue); j++ {
node := queue[j]
if node != nil {
result = append(result, node.Val)
queue = append(queue, node.Left)
queue = append(queue, node.Right)
} else {
result = append(result, -1)
}
}
// 清除队列中的本层节点, 进入下一层遍历
queue = queue[len(queue):]
}
// 参数n控制输出值数量, 否则二叉树最后一层叶子节点的孩子节点也会被打印(但是这些孩子节点是不存在的).
fmt.Println(result[:n])
}
func main() {
array := []int{4, 1, 6, 0, 2, 5, 7, -1, -1, -1, 3, -1, -1, -1, 8}
root := constructBinaryTree(array)
printBinaryTree(root, len(array))
}
```
## JavaScript

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@ -76,7 +76,7 @@
* 空间复杂度:$O(n)$递归深度为n所以系统栈所用空间为$O(n)$每一层递归所用的空间都是常数级别注意代码里的result和path都是全局变量就算是放在参数里传的也是引用并不会新申请内存空间最终空间复杂度为$O(n)$。
排列问题分析:
* 时间复杂度:$O(n!)$这个可以从排列的树形图中很明显发现每一层节点为n第二层每一个分支都延伸了n-1个分支再往下又是n-2个分支所以一直到叶子节点一共就是 n * n-1 * n-2 * ..... 1 = n!。
* 时间复杂度:$O(n!)$这个可以从排列的树形图中很明显发现每一层节点为n第二层每一个分支都延伸了n-1个分支再往下又是n-2个分支所以一直到叶子节点一共就是 n * n-1 * n-2 * ..... 1 = n!。每个叶子节点都会有一个构造全排列填进数组的操作(对应的代码:`result.push_back(path)`),该操作的复杂度为$O(n)$。所以最终时间复杂度为n * n!,简化为$O(n!)$。
* 空间复杂度:$O(n)$,和子集问题同理。
组合问题分析:

View File

@ -365,6 +365,87 @@ class Solution:
return res
```
TypeScript
**90.子集II**
```typescript
function subsetsWithDup(nums: number[]): number[][] {
nums.sort((a, b) => a - b);
const resArr: number[][] = [];
backTraking(nums, 0, []);
return resArr;
function backTraking(nums: number[], startIndex: number, route: number[]): void {
resArr.push(route.slice());
const helperSet: Set<number> = new Set();
for (let i = startIndex, length = nums.length; i < length; i++) {
if (helperSet.has(nums[i])) continue;
helperSet.add(nums[i]);
route.push(nums[i]);
backTraking(nums, i + 1, route);
route.pop();
}
}
};
```
**40. 组合总和 II**
```typescript
function combinationSum2(candidates: number[], target: number): number[][] {
candidates.sort((a, b) => a - b);
const resArr: number[][] = [];
backTracking(candidates, target, 0, 0, []);
return resArr;
function backTracking(
candidates: number[], target: number,
curSum: number, startIndex: number, route: number[]
) {
if (curSum > target) return;
if (curSum === target) {
resArr.push(route.slice());
return;
}
const helperSet: Set<number> = new Set();
for (let i = startIndex, length = candidates.length; i < length; i++) {
let tempVal: number = candidates[i];
if (helperSet.has(tempVal)) continue;
helperSet.add(tempVal);
route.push(tempVal);
backTracking(candidates, target, curSum + tempVal, i + 1, route);
route.pop();
}
}
};
```
**47. 全排列 II**
```typescript
function permuteUnique(nums: number[]): number[][] {
const resArr: number[][] = [];
const usedArr: boolean[] = [];
backTracking(nums, []);
return resArr;
function backTracking(nums: number[], route: number[]): void {
if (nums.length === route.length) {
resArr.push(route.slice());
return;
}
const usedSet: Set<number> = new Set();
for (let i = 0, length = nums.length; i < length; i++) {
if (usedArr[i] === true || usedSet.has(nums[i])) continue;
usedSet.add(nums[i]);
route.push(nums[i]);
usedArr[i] = true;
backTracking(nums, route);
usedArr[i] = false;
route.pop();
}
}
};
```
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