Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

Sign up
Appearance settings

[pull] master from youngyangyang04:master #71

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
pull merged 5 commits into AlgorithmAndLeetCode:master from youngyangyang04:master
Aug 29, 2022
Merged
Changes from 1 commit
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Prev Previous commit
Next Next commit
347.前K个高频元素JS版本修改
  • Loading branch information
Jamcy123 committed Aug 23, 2022
commit 300922d68e3305024755fffb718f5d07a05b70cd
155 changes: 79 additions & 76 deletions problems/0347.前K个高频元素.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -263,99 +263,102 @@ func topKFrequent(nums []int, k int) []int {



javaScript:
JavaScript:
```js
/**
* @param {number[]} nums
* @param {number} k
* @return {number[]}
*/
var topKFrequent = function(nums, k) {
const map = new Map();

for(const num of nums) {
map.set(num, (map.get(num) || 0) + 1);
}

// 创建小顶堆
const priorityQueue = new PriorityQueue((a, b) => a[1] - b[1]);

// entry 是一个长度为2的数组,0位置存储key,1位置存储value
for (const entry of map.entries()) {
priorityQueue.push(entry);
if (priorityQueue.size() > k) {
priorityQueue.pop();
// js 没有堆 需要自己构造
class Heap {
constructor(compareFn) {
this.compareFn = compareFn;
this.queue = [];
}
}

const ret = [];
// 添加
push(item) {
// 推入元素
this.queue.push(item);

for(let i = priorityQueue.size() - 1; i >= 0; i--) {
ret[i] = priorityQueue.pop()[0];
}
// 上浮
let index = this.size() - 1; // 记录推入元素下标
let parent = Math.floor((index - 1) / 2); // 记录父节点下标

return ret;
};
while (parent >= 0 && this.compare(parent, index) > 0) { // 注意compare参数顺序
[this.queue[index], this.queue[parent]] = [this.queue[parent], this.queue[index]];

// 更新下标
index = parent;
parent = Math.floor((index - 1) / 2);
}
}

function PriorityQueue(compareFn) {
this.compareFn = compareFn;
this.queue = [];
}
// 获取堆顶元素并移除
pop() {
// 堆顶元素
const out = this.queue[0];

// 添加
PriorityQueue.prototype.push = function(item) {
this.queue.push(item);
let index = this.queue.length - 1;
let parent = Math.floor((index - 1) / 2);
// 上浮
while(parent >= 0 && this.compare(parent, index) > 0) {
// 交换
[this.queue[index], this.queue[parent]] = [this.queue[parent], this.queue[index]];
index = parent;
parent = Math.floor((index - 1) / 2);
}
}
// 移除堆顶元素 填入最后一个元素
this.queue[0] = this.queue.pop();

// 获取堆顶元素并移除
PriorityQueue.prototype.pop = function() {
const ret = this.queue[0];
// 下沉
let index = 0; // 记录下沉元素下标
let left = 1; // left 是左子节点下标 left + 1 则是右子节点下标
let searchChild = this.compare(left, left + 1) > 0 ? left + 1 : left;

// 把最后一个节点移到堆顶
this.queue[0] = this.queue.pop();
while (searchChild !== undefined && this.compare(index, searchChild) > 0) { // 注意compare参数顺序
[this.queue[index], this.queue[searchChild]] = [this.queue[searchChild], this.queue[index]];

let index = 0;
// 左子节点下标,left + 1 就是右子节点下标
let left = 1;
let selectedChild = this.compare(left, left + 1) > 0 ? left + 1 : left;
// 更新下标
index = searchChild;
left = 2 * index + 1;
searchChild = this.compare(left, left + 1) > 0 ? left + 1 : left;
}

// 下沉
while(selectedChild !== undefined && this.compare(index, selectedChild) > 0) {
// 交换
[this.queue[index], this.queue[selectedChild]] = [this.queue[selectedChild], this.queue[index]];
index = selectedChild;
left = 2 * index + 1;
selectedChild = this.compare(left, left + 1) > 0 ? left + 1 : left;
}
return out;
}

return ret;
}
size() {
return this.queue.length;
}

PriorityQueue.prototype.size = function() {
return this.queue.length;
}
// 使用传入的 compareFn 比较两个位置的元素
compare(index1, index2) {
// 处理下标越界问题
if (this.queue[index1] === undefined) return 1;
if (this.queue[index2] === undefined) return -1;

// 使用传入的 compareFn 比较两个位置的元素
PriorityQueue.prototype.compare = function(index1, index2) {
if (this.queue[index1] === undefined) {
return 1;
}
if (this.queue[index2] === undefined) {
return -1;
}
return this.compareFn(this.queue[index1], this.queue[index2]);
}

return this.compareFn(this.queue[index1], this.queue[index2]);
}

const topKFrequent = function (nums, k) {
const map = new Map();

for (const num of nums) {
map.set(num, (map.get(num) || 0) + 1);
}

// 创建小顶堆
const heap= new Heap((a, b) => a[1] - b[1]);

// entry 是一个长度为2的数组,0位置存储key,1位置存储value
for (const entry of map.entries()) {
heap.push(entry);

if (heap.size() > k) {
heap.pop();
}
}

// return heap.queue.map(e => e[0]);

const res = [];

for (let i = heap.size() - 1; i >= 0; i--) {
res[i] = heap.pop()[0];
}

return res;
};
```

TypeScript:
Expand Down

AltStyle によって変換されたページ (->オリジナル) /