[프로그래머스 Lv.2] 힙(Heap) - 더 맵게

✨ 문제 ✨

✨ 정답 ✨

// 해당 문제는 Heap 구조를 활용해야 함
class MinHeap {
  constructor() {
    this.heap = [];
  }

  size() {
    return this.heap.length;
  }
      
    // 값을 넣되, 오름차 순 정렬함
  push(value) {
    this.heap.push(value);
    let currentIndex = this.heap.length - 1;

    while (
      currentIndex > 0 &&
      this.heap[currentIndex] < this.heap[Math.floor((currentIndex - 1) / 2)]
    ) {
      const temp = this.heap[currentIndex];
      this.heap[currentIndex] = this.heap[Math.floor((currentIndex - 1) / 2)];
      this.heap[Math.floor((currentIndex - 1) / 2)] = temp;
      currentIndex = Math.floor((currentIndex - 1) / 2);
    }
  }

    // 값을 빼되, 오름차 순 정렬 함
  pop() {
    if (this.heap.length === 0) return null;
    if (this.heap.length === 1) return this.heap.pop();

    const minValue = this.heap[0];
    this.heap[0] = this.heap.pop();
    let currentIndex = 0;

    while (currentIndex * 2 + 1 < this.heap.length) {
      let minChildIndex = currentIndex * 2 + 2 < this.heap.length && this.heap[currentIndex * 2 + 2] < this.heap[currentIndex * 2 + 1] ? currentIndex * 2 + 2 : currentIndex * 2 + 1;

      if (this.heap[currentIndex] < this.heap[minChildIndex]) {
        break;
      }

      const temp = this.heap[currentIndex];
      this.heap[currentIndex] = this.heap[minChildIndex];
      this.heap[minChildIndex] = temp;
      currentIndex = minChildIndex;
    }

    return minValue;
  }

  peek() {
    return this.heap[0];
  }
}

function solution(scoville, K) {
  const minHeap = new MinHeap();

  for (const sco of scoville) {
    minHeap.push(sco);
  }

  let mixedCount = 0;

  while (minHeap.size() >= 2 && minHeap.peek() < K) {
    const first = minHeap.pop();
    const second = minHeap.pop();
    const mixedScov = first + second * 2;
    minHeap.push(mixedScov);
    mixedCount++;
  }

  return minHeap.peek() >= K ? mixedCount : -1;
}

🧵 참고한 정답지 🧵

https://velog.io/@kwb020312/%ED%94%84%EB%A1%9C%EA%B7%B8%EB%9E%98%EB%A8%B8%EC%8A%A4-%EB%8D%94-%EB%A7%B5%EA%B2%8C

💡💡 기억해야 할 점 💡💡