这是在C＃中经过测试的完整解决方案（很抱歉，我不是Java开发人员）（只需在控制台应用程序中复制粘贴）。我知道平衡的定义会有所不同，因此并不是每个人都喜欢我的测试结果，但请看看在递归循环中检查深度/高度并在第一次不匹配时退出而又不保存每个节点的节点高度/级别/深度的稍微不同的方法（仅在函数调用中进行维护）。
using System;
using System.Linq;
using System.Text;
namespace BalancedTree
{
class Program
{
public static void Main()
{
//Value Gathering
Console.WriteLine(RunTreeTests(new[] { 0 }));
Console.WriteLine(RunTreeTests(new int[] { }));
Console.WriteLine(RunTreeTests(new[] { 0, 1, 2, 3, 4, -1, -4, -3, -2 }));
Console.WriteLine(RunTreeTests(null));
Console.WriteLine(RunTreeTests(new[] { 10, 8, 12, 8, 4, 14, 8, 10 }));
Console.WriteLine(RunTreeTests(new int[] { 20, 10, 30, 5, 15, 25, 35, 3, 8, 12, 17, 22, 27, 32, 37 }));
Console.ReadKey();
}
static string RunTreeTests(int[] scores)
{
if (scores == null || scores.Count() == 0)
{
return null;
}
var tree = new BinarySearchTree();
foreach (var score in scores)
{
tree.InsertScore(score);
}
Console.WriteLine(tree.IsBalanced());
var sb = tree.GetBreadthWardsTraversedNodes();
return sb.ToString(0, sb.Length - 1);
}
}
public class Node
{
public int Value { get; set; }
public int Count { get; set; }
public Node RightChild { get; set; }
public Node LeftChild { get; set; }
public Node(int value)
{
Value = value;
Count = 1;
}
public override string ToString()
{
return Value + ":" + Count;
}
public bool IsLeafNode()
{
return LeftChild == null && RightChild == null;
}
public void AddValue(int value)
{
if (value == Value)
{
Count++;
}
else
{
if (value > Value)
{
if (RightChild == null)
{
RightChild = new Node(value);
}
else
{
RightChild.AddValue(value);
}
}
else
{
if (LeftChild == null)
{
LeftChild = new Node(value);
}
else
{
LeftChild.AddValue(value);
}
}
}
}
}
public class BinarySearchTree
{
public Node Root { get; set; }
public void InsertScore(int score)
{
if (Root == null)
{
Root = new Node(score);
}
else
{
Root.AddValue(score);
}
}
private static int _heightCheck;
public bool IsBalanced()
{
_heightCheck = 0;
var height = 0;
if (Root == null) return true;
var result = CheckHeight(Root, ref height);
height--;
return (result && height == 0);
}
private static bool CheckHeight(Node node, ref int height)
{
height++;
if (node.LeftChild == null)
{
if (node.RightChild != null) return false;
if (_heightCheck != 0) return _heightCheck == height;
_heightCheck = height;
return true;
}
if (node.RightChild == null)
{
return false;
}
var leftCheck = CheckHeight(node.LeftChild, ref height);
if (!leftCheck) return false;
height--;
var rightCheck = CheckHeight(node.RightChild, ref height);
if (!rightCheck) return false;
height--;
return true;
}
public StringBuilder GetBreadthWardsTraversedNodes()
{
if (Root == null) return null;
var traversQueue = new StringBuilder();
traversQueue.Append(Root + ",");
if (Root.IsLeafNode()) return traversQueue;
TraversBreadthWards(traversQueue, Root);
return traversQueue;
}
private static void TraversBreadthWards(StringBuilder sb, Node node)
{
if (node == null) return;
sb.Append(node.LeftChild + ",");
sb.Append(node.RightChild + ",");
if (node.LeftChild != null && !node.LeftChild.IsLeafNode())
{
TraversBreadthWards(sb, node.LeftChild);
}
if (node.RightChild != null && !node.RightChild.IsLeafNode())
{
TraversBreadthWards(sb, node.RightChild);
}
}
}
}