algorithm/hello-algo
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Fine tune

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This commit is contained in:
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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94
codes/csharp/chapter_tree/binary_tree_bfs.cs
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@@ -17,17 +17,17 @@ namespace hello_algo.chapter_tree
/// </summary>
/// <param name="root"></param>
/// <returns></returns>
public List<int?> hierOrder(TreeNode root)
public List<int> hierOrder(TreeNode root)
{
// 初始化队列，加入根结点
Queue<TreeNode> queue = new();
queue.Enqueue(root);
// 初始化一个列表，用于保存遍历序列
List<int?> list = new();
List<int> list = new();
while (queue.Count != 0)
{
TreeNode node = queue.Dequeue(); // 队列出队
list.Add(node.val); // 保存结点值
TreeNode node = queue.Dequeue(); // 队列出队
list.Add(node.val); // 保存结点值
if (node.left != null)
queue.Enqueue(node.left); // 左子结点入队
if (node.right != null)
@@ -36,88 +36,18 @@ namespace hello_algo.chapter_tree
return list;
}
List<int?> list = new();
/// <summary>
/// 前序遍历
/// </summary>
/// <param name="root"></param>
void preOrder(TreeNode? root)
{
if (root == null) return;
// 访问优先级：根结点 -> 左子树 -> 右子树
list.Add(root.val);
preOrder(root.left);
preOrder(root.right);
}
/// <summary>
/// 中序遍历
/// </summary>
/// <param name="root"></param>
void inOrder(TreeNode? root)
{
if (root == null) return;
// 访问优先级：左子树 -> 根结点 -> 右子树
inOrder(root.left);
list.Add(root.val);
inOrder(root.right);
}
/// <summary>
/// 后序遍历
/// </summary>
/// <param name="root"></param>
void postOrder(TreeNode? root)
{
if (root == null) return;
// 访问优先级：左子树 -> 右子树 -> 根结点
postOrder(root.left);
postOrder(root.right);
list.Add(root.val);
}
/// <summary>
/// 辅助函数,数组转字符串
/// </summary>
public static string ToString(int?[] nums)
{
return string.Join(",", nums);
}
[Test]
public void Test()
{
// 初始化结点
TreeNode root = 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);
// 构建引用指向（即指针）
root.left = n2;
root.right = n3;
n2.left = n4;
n2.right = n5;
n3.left = n6;
n3.right = n7;
/* 初始化二叉树 */
// 这里借助了一个从数组直接生成二叉树的函数
TreeNode? root = TreeNode.ArrToTree(new int?[] {
1, 2, 3, 4, 5, 6, 7, null, null, null, null, null, null, null, null});
Console.WriteLine("\n初始化二叉树\n");
PrintUtil.PrintTree(root);
list = hierOrder(root);
Console.WriteLine("层序遍历 结果 = " + ToString(list.ToArray()));
list = new List<int?>();
preOrder(root);
Console.WriteLine("前序遍历 结果 = " + ToString(list.ToArray()));
list = new List<int?>();
inOrder(root);
Console.WriteLine("中序遍历 结果 = " + ToString(list.ToArray()));
list = new List<int?>();
postOrder(root);
Console.WriteLine("后序遍历 结果 = " + ToString(list.ToArray()));
List<int> list = hierOrder(root);
Console.WriteLine("\n层序遍历的结点打印序列 = " + string.Join(",", list.ToArray()));
}
}
}