Пример #1
0
    private E findStartingNodeForDeletion(E element) {
      if (root == null) return null;

      TreeNode<E> parent = null;
      TreeNode<E> current = root;
      while (current != null) {
        if (element.compareTo(current.element) < 0) {
          parent = current;
          current = current.left;
        } else if (element.compareTo(current.element) > 0) {
          parent = current;
          current = current.right;
        } else break;
      }

      if (current == null) return null;

      if (current.left == null) {
        if (parent == null) {
          return null;
        } else {
          return parent.element;
        }
      } else {
        TreeNode<E> parentOfRightMost = current;
        TreeNode<E> rightMost = current.left;

        while (rightMost.right != null) {
          parentOfRightMost = rightMost;
          rightMost = rightMost.right;
        }
        return parentOfRightMost.element;
      }
    }
Пример #2
0
    public boolean delete(E element) {
      if (root == null) return false;
      TreeNode<E> parent = null;
      TreeNode<E> current = root;
      while (current != null) {
        if (element.compareTo(current.element) < 0) {
          parent = current;
          current = current.left;
        } else if (element.compareTo(current.element) > 0) {
          parent = current;
          current = current.right;
        } else break;
      }
      if (current == null) return false;
      if (current.left == null) {
        if (parent == null) {
          root = current.right;
        } else {
          if (element.compareTo(parent.element) < 0) parent.left = current.right;
          else parent.right = current.right;
          balancePath(parent.element);
        }
      } else {
        TreeNode<E> parentOfRightMost = current;
        TreeNode<E> rightMost = current.left;

        while (rightMost.right != null) {
          parentOfRightMost = rightMost;
          rightMost = rightMost.right;
        }
        current.element = rightMost.element;
        if (parentOfRightMost.right == rightMost) parentOfRightMost.right = rightMost.left;
        else parentOfRightMost.left = rightMost.left;
        balancePath(parentOfRightMost.element);
      }
      size--;
      return true;
    }