1244-design-a-leaderboard.js

const Leaderboard = function() {
  this.hash = {}
};

/** 
 * @param {number} playerId 
 * @param {number} score
 * @return {void}
 */
Leaderboard.prototype.addScore = function(playerId, score) {
  if(this.hash[playerId] == null) this.hash[playerId] = 0
  this.hash[playerId] += score
};

/** 
 * @param {number} K
 * @return {number}
 */
Leaderboard.prototype.top = function(K) {
  const pq = new PriorityQueue((a, b) => a < b)
  const values = Object.values(this.hash)
  // console.log(values)
  for(const v of values) {
    pq.push(v)
    if(pq.size() > K) pq.pop()
  }
  // console.log(pq.heap)
  let sum = 0
  while(!pq.isEmpty()) {
    sum += pq.pop()
    
  }
  
  return sum
};

/** 
 * @param {number} playerId
 * @return {void}
 */
Leaderboard.prototype.reset = function(playerId) {
  delete this.hash[playerId]
};

/** 
 * Your Leaderboard object will be instantiated and called as such:
 * var obj = new Leaderboard()
 * obj.addScore(playerId,score)
 * var param_2 = obj.top(K)
 * obj.reset(playerId)
 */

class PriorityQueue {
  constructor(comparator = (a, b) => a > b) {
    this.heap = []
    this.top = 0
    this.comparator = comparator
  }
  size() {
    return this.heap.length
  }
  isEmpty() {
    return this.size() === 0
  }
  peek() {
    return this.heap[this.top]
  }
  push(...values) {
    values.forEach((value) => {
      this.heap.push(value)
      this.siftUp()
    })
    return this.size()
  }
  pop() {
    const poppedValue = this.peek()
    const bottom = this.size() - 1
    if (bottom > this.top) {
      this.swap(this.top, bottom)
    }
    this.heap.pop()
    this.siftDown()
    return poppedValue
  }
  replace(value) {
    const replacedValue = this.peek()
    this.heap[this.top] = value
    this.siftDown()
    return replacedValue
  }

  parent = (i) => ((i + 1) >>> 1) - 1
  left = (i) => (i << 1) + 1
  right = (i) => (i + 1) << 1
  greater = (i, j) => this.comparator(this.heap[i], this.heap[j])
  swap = (i, j) => ([this.heap[i], this.heap[j]] = [this.heap[j], this.heap[i]])
  siftUp = () => {
    let node = this.size() - 1
    while (node > this.top && this.greater(node, this.parent(node))) {
      this.swap(node, this.parent(node))
      node = this.parent(node)
    }
  }
  siftDown = () => {
    let node = this.top
    while (
      (this.left(node) < this.size() && this.greater(this.left(node), node)) ||
      (this.right(node) < this.size() && this.greater(this.right(node), node))
    ) {
      let maxChild =
        this.right(node) < this.size() &&
        this.greater(this.right(node), this.left(node))
          ? this.right(node)
          : this.left(node)
      this.swap(node, maxChild)
      node = maxChild
    }
  }
}