@coderbaba/stl-js/structures/BinaryTree.ts

STL data structures for JavaScript

class TreeNode<T> {
  value: T;
  left: TreeNode<T> | null = null;
  right: TreeNode<T> | null = null;

  constructor(value: T) {
    this.value = value;
  }
}

class BinaryTree<T> {
  private root: TreeNode<T> | null = null;

  insert(value: T): void {
    const newNode = new TreeNode < T > (value);

    if (!this.root) {
      this.root = newNode;
      return;
    }

    const queue: TreeNode<T>[] = [this.root];

    while (queue.length) {
      const node = queue.shift()!;
      if (!node.left) {
        node.left = newNode;
        return;
      } else {
        queue.push(node.left);
      }

      if (!node.right) {
        node.right = newNode;
        return;
      } else {
        queue.push(node.right);
      }
    }
  }

  inOrder(node: TreeNode<T> | null = this.root, result: T[] = []): T[] {
    if (node) {
      this.inOrder(node.left, result);
      result.push(node.value);
      this.inOrder(node.right, result);
    }
    return result;
  }

  preOrder(node: TreeNode<T> | null = this.root, result: T[] = []): T[] {
    if (node) {
      result.push(node.value);
      this.preOrder(node.left, result);
      this.preOrder(node.right, result);
    }
    return result;
  }

  postOrder(node: TreeNode<T> | null = this.root, result: T[] = []): T[] {
    if (node) {
      this.postOrder(node.left, result);
      this.postOrder(node.right, result);
      result.push(node.value);
    }
    return result;
  }
}

export default BinaryTree;