使用Array在二进制搜索树中查找具有最小值的节点

Question

我有一个整数数组，我需要使用二进制搜索树方法找到这个数组的最小值。我对BST不太自信，但我知道如何在BST中插入和搜索。

我应该执行哪些程序，以便获得最小值。 这是我写的伪代码。

1. 首先在BST中插入数组的值
2. 然后遍历BST以找到最小元素

我不知道我是在正确的道路上还是没有？

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;
    using System.Diagnostics;
    using System.Collections;

    namespace ConsoleApp2

{

    class Program
    {

        public class Node
    {
        public int Data;
        public Node Left;
        public Node Right;
        public void DisplayNode()
        {
            Console.Write(Data + " ");
        }
    }






        public Node root;
            public Program()
            {
                root = null;
            }
            public void Insert(int i)
            {
                Node newNode = new Node();
                newNode.Data = i;
                if (root == null)
                    root = newNode;
                else
                {
                    Node current = root;
                    Node parent;
                    while (true)
                    {
                        parent = current;
                        if (i < current.Data)
                        {
                            current = current.Left;
                            if (current == null)
                            {
                                parent.Left = newNode;
                                break;
                            }

                            else
                            {
                                current = current.Right;
                                if (current == null)
                                {
                                    parent.Right = newNode;
                                    break;
                                }
                            }
                        }
                    }
                }
            }


            static void Main()
            {
             int minvalue(Node node)
            {
                Node current = node;

                /* loop down to find the leftmost leaf */


                    while (current.Left != null)
                    {
                        current = current.Left;
                    }
                    return (current.Data);
                }

            Program nums = new Program();
                nums.Insert(50);
                nums.Insert(17);
                nums.Insert(23);
                nums.Insert(12);
                nums.Insert(19);

            Node root = null;
            int min = minvalue(root);
            Console.WriteLine(min);
            Console.ReadLine();
            }
        }

    }

这是我的解决方案，但我有错误 System.NullReferenceException：'对象引用未设置为对象的实例。' 当前为空。

Answer 1

我修改了你的代码，所以它编译并且结构合理。我没有解决任何编码问题。你必须解决。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Diagnostics;
using System.Collections;

namespace ConsoleApp2

{

    class Program
    {

        static void Main()
        {
            Node nums = new Node();
            nums.Insert(50);
            nums.Insert(17);
            nums.Insert(23);
            nums.Insert(12);
            nums.Insert(19);

            int min = nums.MinValue(nums.root);
            Console.WriteLine(min);
            Console.ReadLine();
        }
    }
    public class Node
    {
        public int Data;
        public Node Left;
        public Node Right;
        public void DisplayNode()
        {
            Console.Write(Data + " ");
        }

        public Node root = null;

        public int MinValue(Node node)
        {

            Node current = node;

            /* loop down to find the leftmost leaf */


            while (current.Left != null)
            {
                current = current.Left;
            }
            return (current.Data);
        }

        public void Insert(int i)
        {
            Node newNode = new Node();
            newNode.Data = i;
            if (root == null)
                root = newNode;
            else
            {
                Node current = root;
                Node parent;
                while (true)
                {
                    parent = current;
                    if (i < current.Data)
                    {
                        current = current.Left;
                        if (current == null)
                        {
                            parent.Left = newNode;
                            break;
                        }

                        else
                        {
                            current = current.Right;
                            if (current == null)
                            {
                                parent.Right = newNode;
                                break;
                            }
                        }
                    }
                }
            }
        }
    }

}