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HTML 

              
                <!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>二叉堆</title>
</head>

<body>
  <h1 style="text-align:center;">最小堆算法</h1>
</body>

</html>
!

CSS
!

JS 

              
                // 最小二叉堆，所有节点都小于等于它的两个子节点,所以根节点一定是最小的值

// class MinHeap {
//   constructor() {
//     this.heap = [];
//   }

//   insert(val) {
//     if (this.size() === 0) {
//       this.heap.push(val);
//     } else {
//       this.heap.push(val);
//       this.siftUp(this.heap.length - 1);
//     }
//   }

//   siftUp(index) {
//     let parent = this.parent(index);
//     while (this.heap[parent] > this.heap[index]) {
//       const temp = this.heap[parent];
//       this.heap[parent] = this.heap[index];
//       this.heap[index] = temp;
//       index = parent;
//       parent = this.parent(parent);
//     }
//   }

//   extract() {
//     if (this.size() <= 2) {
//       return this.heap.shift();
//     } else {
//       const result = this.heap[0];
//       this.heap[0] = this.heap.pop();
//       this.siftDown(0);
//       return result;
//     }
//   }

//   siftDown(index) {
//     let leftChild = this.leftChild(index);
//     let rightChild = this.rightChild(index);
//     let current = index;
//     if (
//       typeof this.heap[leftChild] !== undefined &&
//       this.heap[leftChild] < this.heap[current]
//     ) {
//       current = leftChild;
//     }
//     if (
//       typeof this.heap[rightChild] !== undefined &&
//       this.heap[rightChild] < this.heap[current]
//     ) {
//       current = rightChild;
//     }
//     // current is the maximum node
//     if (current !== index) {
//       const temp = this.heap[index];
//       this.heap[index] = this.heap[current];
//       this.heap[current] = temp;
//       this.siftDown(current);
//     }
//   }

//   size() {
//     return this.heap.length;
//   }

//   leftChild(index) {
//     return 2 * index + 1;
//   }

//   rightChild(index) {
//     return 2 * index + 2;
//   }

//   parent(index) {
//     return Math.floor((index - 1) / 2);
//   }

//   display() {
//     console.log(this.heap);
//   }

//   findMinimum() {
//     return this.head[0];
//   }
// }

class MinHeap {
  constructor() {
    this.heap = [];
  }

  insert(val) {
    if (!this.heap.length) {
      this.heap.push(val);
    } else {
      this.heap.push(val);
      this._siftUp(this.heap.length - 1);
    }
  }

  extract() {
    const result = this.heap.shift();
    if (this.heap.length > 1) {
      const last = this.heap.pop();
      this.heap.unshift(last);
      this._siftDown(0);
    }

    return result;
  }

  _siftUp(index) {
    const parent = this.parent(index);
    if (parent < 0) return;
    const { heap } = this;
    if (heap[parent] > heap[index]) {
      [heap[parent], heap[index]] = [heap[index], heap[parent]];
      this._siftUp(parent);
    }
  }

  _siftDown(index) {
    let current = index;
    const { heap } = this;
    const left = this.leftChild(index);
    const right = this.rightChild(index);
    let next = current;
    if (heap[left] && heap[left] < heap[current]) {
      next = left;
    }
    if (heap[right] && heap[right] < heap[current]) {
      next = right;
    }

    if (next !== current) {
      [heap[next], heap[current]] = [heap[current], heap[next]];
      this._siftDown(next);
    }
  }

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

  display() {
    console.log(this.heap);
  }
  leftChild(index) {
    return index * 2 + 1;
  }
  rightChild(index) {
    return index * 2 + 2;
  }
  parent(index) {
    return Math.floor((index - 1) / 2);
  }
}

// 堆排序

// class MaxHeap {
//   constructor() {
//     this.heap = [];
//   }

//   insert(val) {
//     const { heap } = this;
//     heap.push(val);
//     if (heap.length > 1) {
//       this._siftUp(heap.length - 1);
//     }
//   }

//   _siftUp(index) {
//     if (index === 0) return;
//     const { heap } = this;
//     const parent = this.parent(index);
//     if (heap[parent] < heap[index]) {
//       [heap[parent], heap[index]] = [heap[index], heap[parent]];
//       this._siftUp(parent);
//     }
//   }

//   sort() {
//     const { heap } = this;
//     let length = heap.length - 1;
//     while (length > 1) {
//       [heap[0], heap[length]] = [heap[length], heap[0]];
//       this._siftDown(0, length--);
//     }
//   }

//   _siftDown(index, last) {
//     const { heap } = this;
//     let current = index;
//     const left = this.leftChild(current);
//     const right = this.rightChild(current);
//     if (left >= last || right >= last) return;
//     if (heap[current] < heap[left]) {
//       current = left;
//     }
//     if (heap[current] < heap[right]) {
//       current = right;
//     }

//     if (current !== index) {
//       [heap[current], heap[index]] = [heap[index], heap[current]];
//       this._siftDown(current, last);
//     }
//   }

//   leftChild(index) {
//     return 2 * index + 1;
//   }

//   rightChild(index) {
//     return 2 * index + 2;
//   }
//   parent(index) {
//     return Math.floor((index - 1) / 2);
//   }

//   display() {
//     console.log(this.heap);
//   }
// }

const minHeap = new MinHeap();
minHeap.insert(2);
minHeap.insert(2);
minHeap.insert(6);
minHeap.insert(5);
minHeap.insert(4);
minHeap.insert(3);
minHeap.insert(1);

// minHeap.sort();
// minHeap.extract();
// minHeap.extract();
minHeap.display();
!
999px

Console