LeetCode：347.前K个高频元素
var topKFrequent = function(nums, k) {let map=new Map();let arr=[...new Set(nums)]nums.forEach(item=>{if(map.has(item)){map.set(item,map.get(item)+1)}else{map.set(item,1)}})return arr.sort((a,b)=>map.get(b)-map.get(a)).slice(0,k)
};class MinHeap {constructor() {this.heap = []this.len = 0}size() {return this.len}push(val) {this.heap[++this.len] = valthis.swin(this.len)}pop() {const ret = this.heap[1]this.swap(1, this.len--)this.heap[this.len + 1] = nullthis.sink(1)return ret}swin(ind) {while (ind > 1 && this.less(ind, parseInt(ind / 2))) {this.swap(ind, parseInt(ind / 2))ind = parseInt(ind / 2)}}sink(ind) {while (ind * 2 <= this.len) {let j = ind * 2if (j < this.len && this.less(j + 1, j)) j++if (this.less(ind, j)) breakthis.swap(ind, j)ind = j}}top() {return this.heap[1]}isEmpty() {return this.len === 0}swap(i, j) {[this.heap[i], this.heap[j]] = [this.heap[j], this.heap[i]]}less(i, j) {return this.heap[i].val < this.heap[j].val}getHeap() {return this.heap}}
/*** @param {number[]} nums* @param {number} k* @return {number[]}*/
var topKFrequent = function(nums, k) {let map=new Map();nums.forEach(item=>{if(map.has(item)){map.set(item,map.get(item)+1)}else{map.set(item,1)}})let h=new MinHeap();map.forEach((val,key)=>{h.push({val,key});if(h.size()>k) h.pop();})return h.heap.filter(item=>item&&item.val).map(item=>item.key);
};
