09.30: priority queue(신입사원 교육)

programmers/신입사원 교육.js

@@ -0,0 +1,85 @@
+// 신입사원 교육: 우선순위 큐
+class Heap {
+  constructor() {
+    this.arr = [null];
+    this.size = 0;
+  }
+
+  push(number) {
+    this.arr.push(number);
+    this.size++;
+
+    let curr = this.size;
+    let parent = Math.floor(curr / 2);
+    while (curr !== 1) {
+      if (this.arr[curr] < this.arr[parent]) {
+        [this.arr[curr], this.arr[parent]] = [this.arr[parent], this.arr[curr]];
+      }
+      curr = parent;
+      parent = Math.floor(curr / 2);
+    }
+  }
+
+  pop() {
+    if (this.size === 0) {
+      return null;
+    } else if (this.size === 1) {
+      this.size--;
+      return this.arr.pop();
+    }
+    this.size--;
+    const top = this.arr[1];
+    this.arr[1] = this.arr.pop();
+    let curr = 1;
+    let left = curr * 2;
+    let right = left + 1;
+
+    while (true) {
+      if (this.arr[left] === undefined) {
+        break;
+      } else if (this.arr[right] === undefined) {
+        if (this.arr[curr] > this.arr[left]) {
+          [this.arr[curr], this.arr[left]] = [this.arr[left], this.arr[curr]];
+        }
+        curr = left;
+        left = curr * 2;
+        right = left + 1;
+      } else {
+        const isLeftSmall = this.arr[left] < this.arr[right];
+        if (isLeftSmall) {
+          if (this.arr[curr] > this.arr[left]) {
+            [this.arr[curr], this.arr[left]] = [this.arr[left], this.arr[curr]];
+          }
+        } else {
+          if (this.arr[curr] > this.arr[right]) {
+            [this.arr[curr], this.arr[right]] = [
+              this.arr[right],
+              this.arr[curr],
+            ];
+          }
+        }
+        curr = isLeftSmall ? left : right;
+        left = curr * 2;
+        right = left + 1;
+      }
+    }
+    return top;
+  }
+}
+
+function solution(ability, number) {
+  var answer = 0;
+  const heap = new Heap();
+  for (const ab of ability) {
+    heap.push(ab);
+    answer += ab;
+  }
+  for (let i = 0; i < number; i++) {
+    const first = heap.pop();
+    const second = heap.pop();
+    answer += first + second;
+    heap.push(first + second);
+    heap.push(first + second);
+  }
+  return answer;
+}