algorithm/hello-algo
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Yudong Jin
2022-12-24 16:15:41 +08:00
parent 3339a648d0
commit b1645c7d7e
24 changed files with 235 additions and 233 deletions
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101
codes/csharp/chapter_tree/binary_search_tree.cs
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@ -9,16 +9,38 @@ using NUnit.Framework;
namespace hello_algo.chapter_tree
{
internal class binary_search_tree
class BinarySearchTree
{
TreeNode? root;
public BinarySearchTree(int[] nums) {
Array.Sort(nums); // 排序数组
root = buildTree(nums, 0, nums.Length - 1); // 构建二叉搜索树
}
/* 获取二叉树根结点 */
public TreeNode? getRoot() {
return root;
}
/* 构建二叉搜索树 */
public TreeNode? buildTree(int[] nums, int i, int j) {
if (i > j) return null;
// 将数组中间结点作为根结点
int mid = (i + j) / 2;
TreeNode root = new TreeNode(nums[mid]);
// 递归建立左子树和右子树
root.left = buildTree(nums, i, mid - 1);
root.right = buildTree(nums, mid + 1, j);
return root;
}
/// <summary>
/// 查找结点
/// </summary>
/// <param name="num"></param>
/// <returns></returns>
TreeNode? search(int num)
public TreeNode? search(int num)
{
TreeNode? cur = root;
// 循环查找，越过叶结点后跳出
@ -36,7 +58,7 @@ namespace hello_algo.chapter_tree
}
/* 插入结点 */
TreeNode? insert(int num)
public TreeNode? insert(int num)
{
// 若树为空，直接提前返回
if (root == null) return null;
@ -65,7 +87,7 @@ namespace hello_algo.chapter_tree
/* 删除结点 */
TreeNode? remove(int? num)
public TreeNode? remove(int num)
{
// 若树为空，直接提前返回
if (root == null) return null;
@ -106,7 +128,7 @@ namespace hello_algo.chapter_tree
TreeNode? nex = min(cur.right);
if (nex != null)
{
int? tmp = nex.val;
int tmp = nex.val;
// 递归删除结点 nex
remove(nex.val);
// 将 nex 的值复制给 cur
@ -117,7 +139,7 @@ namespace hello_algo.chapter_tree
}
/* 获取最小结点 */
TreeNode? min(TreeNode? root)
private TreeNode? min(TreeNode? root)
{
if (root == null) return root;
// 循环访问左子结点，直到叶结点时为最小结点，跳出
@ -127,55 +149,38 @@ namespace hello_algo.chapter_tree
}
return root;
}
}
public class binary_search_tree
{
[Test]
public void Test()
{
// 初始化结点
TreeNode n1 = new TreeNode(1);
TreeNode n2 = new TreeNode(2);
TreeNode n3 = new TreeNode(3);
TreeNode n4 = new TreeNode(4);
TreeNode n5 = new TreeNode(5);
TreeNode n6 = new TreeNode(6);
TreeNode n7 = new TreeNode(7);
TreeNode n8 = new TreeNode(8);
TreeNode n9 = new TreeNode(9);
TreeNode n10 = new TreeNode(10);
TreeNode n11 = new TreeNode(11);
TreeNode n12 = new TreeNode(12);
TreeNode n13 = new TreeNode(13);
TreeNode n14 = new TreeNode(14);
TreeNode n15 = new TreeNode(15);
root = n8;
root.left = n4;
root.right = n12;
n4.left = n2;
n4.right = n6;
n12.left = n10;
n12.right = n14;
n2.left = n1;
n2.right = n3;
n6.left = n5;
n6.right = n7;
n10.left = n9;
n10.right = n11;
n14.left = n13;
n14.right = n15;
/* 初始化二叉搜索树 */
int[] nums = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
BinarySearchTree bst = new BinarySearchTree(nums);
Console.WriteLine("\n初始化的二叉树为\n");
PrintUtil.PrintTree(bst.getRoot());
var cur = search(7);
Console.WriteLine("查找结点 结果 = " + cur?.val);
/* 查找结点 */
TreeNode? node = bst.search(5);
Console.WriteLine("\n查找到的结点对象为 " + node + "，结点值 = " + node.val);
var node = insert(16);
Console.WriteLine("插入结点 结果 = " + node?.val);
node = remove(1);
Console.WriteLine("删除结点 结果 = " + node?.val);
node = remove(2);
Console.WriteLine("删除结点 结果 = " + node?.val);
node = remove(4);
Console.WriteLine("删除结点 结果 = " + node?.val);
/* 插入结点 */
node = bst.insert(16);
Console.WriteLine("\n插入结点 16 后，二叉树为\n");
PrintUtil.PrintTree(bst.getRoot());
/* 删除结点 */
bst.remove(1);
Console.WriteLine("\n删除结点 1 后，二叉树为\n");
PrintUtil.PrintTree(bst.getRoot());
bst.remove(2);
Console.WriteLine("\n删除结点 2 后，二叉树为\n");
PrintUtil.PrintTree(bst.getRoot());
bst.remove(4);
Console.WriteLine("\n删除结点 4 后，二叉树为\n");
PrintUtil.PrintTree(bst.getRoot());
}
}
}