Create 2462-total-cost-to-hire-k-workers.js

Author: everthis

2462-total-cost-to-hire-k-workers.js

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+/**
+ * @param {number[]} costs
+ * @param {number} k
+ * @param {number} candidates
+ * @return {number}
+ */
+const totalCost = function(costs, k, candidates) {
+  const fn = (a, b) => a[0] === b[0] ? a[1] < b[1] : a[0] < b[0]
+  const n = costs.length
+  let l = 0, r = n - 1
+  const first = new PriorityQueue(fn)
+  const last = new PriorityQueue(fn)
+  
+  for(let i = 0; i < Math.min(candidates, n); i++) {
+    first.push([costs[i], i])
+    l = i
+  }
+  
+  for(let i = n - 1; i > Math.max(0, candidates - 1, n - 1 - candidates); i--) {
+    last.push([costs[i], i])
+    r = i
+  }
+  
+  // console.log(first, last)
+  
+  let res = 0
+  let num = k
+  while(num) {
+    const ft = first.peek()
+    const lt = last.peek()
+    
+    if(ft && lt) {
+      if(ft[0] < lt[0]) {
+        first.pop()
+        res += ft[0]
+        if(r - l > 1) {
+          l++
+          first.push([costs[l], l])
+        }
+      } else if(ft[0] > lt[0]) {
+        last.pop()
+        res += lt[0]
+        if(r - l > 1) {
+          r--
+          last.push([costs[r], r])
+        }
+      } else {
+        first.pop()
+        res += ft[0]
+        if(r - l > 1) {
+          l++
+          first.push([costs[l], l])
+        } 
+      }
+    } else if(ft) {
+      first.pop()
+      res += ft[0]
+    } else if(lt) {
+      last.pop()
+      res += lt[0]
+    }
+    // console.log(res)
+    num--
+  }
+  
+  
+  return res
+  
+};
+
+
+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
+    }
+  }
+}