From 703751283818bb7bdc04c5c601e1b144368d7992 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=BE=A1=E5=9D=82=E6=98=B4?= <gugugulaocuchen@gmail.com>
Date: Fri, 22 Nov 2024 17:16:02 +0800
Subject: [PATCH] =?UTF-8?q?=E7=AC=AC=E4=BA=8C=E9=A2=98=E5=88=9D=E6=AD=A5?=
 =?UTF-8?q?=E5=AE=8C=E6=88=90?=
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---
 homework4/BiTree.cpp     | 35 ++++++++++++++++++++++++++++++++
 homework4/BiTree.h       |  5 +++--
 homework4/CMakeLists.txt |  4 ++++
 homework4/test2.cpp      | 44 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 86 insertions(+), 2 deletions(-)
 create mode 100644 homework4/test2.cpp

diff --git a/homework4/BiTree.cpp b/homework4/BiTree.cpp
index 52d48ca..fca0d70 100644
--- a/homework4/BiTree.cpp
+++ b/homework4/BiTree.cpp
@@ -60,6 +60,29 @@ void BiTree::insertNode(BiTree*& bt, int value)
     }
 }
 
+BiTree* BiTree::build_from_preorder_string(const std::string& preorder, size_t& index)
+{
+    if (index >= preorder.size() || preorder[index] == '#')
+    {
+        index++;
+        return nullptr;
+    }
+
+    BiTree* node = createNode(preorder[index++] - 'A' + 1);
+    node->left = build_from_preorder_string(preorder, index);
+    node->right = build_from_preorder_string(preorder, index);
+
+    return node;
+}
+
+void BiTree::inOrder(std::ostringstream& oss) const
+{
+    if (this == nullptr) return;
+    if (left)left->inOrder(oss);
+    oss << static_cast<char>(data + 'A' - 1);
+    if (right)right->inOrder(oss);
+}
+
 
 void toStringHelper(const BiTree* node, std::ostringstream& oss, const std::string& prefix, bool isLeft,
                     bool hasSibling)
@@ -85,3 +108,15 @@ std::string BiTree::toString()
     return oss.str();
 }
 
+void BiTree::destory()
+{
+    if (left)
+    {
+        left->destory();
+    }
+    if (right)
+    {
+        right->destory();
+    }
+}
+
diff --git a/homework4/BiTree.h b/homework4/BiTree.h
index 50fae67..5967e8b 100644
--- a/homework4/BiTree.h
+++ b/homework4/BiTree.h
@@ -2,7 +2,6 @@
 #define BITREE_H
 #include<sstream>
 
-
 class BiTree
 {
 public:
@@ -10,13 +9,15 @@ public:
     BiTree* left;
     BiTree* right;
 
-
     static bool is_empty(BiTree* bt);
     static bool is_leaf(BiTree* bt);
     static int sum_leaf(BiTree* bt);
     static BiTree* createNode(int data);
     static void insertNode(BiTree*& bt, int value);
+    static BiTree* build_from_preorder_string(const std::string& preorder, size_t& index);
+    void inOrder(std::ostringstream& oss) const;
     std::string toString();
+    void destory();
 };
 
 
diff --git a/homework4/CMakeLists.txt b/homework4/CMakeLists.txt
index 8d9ddca..786c5ad 100644
--- a/homework4/CMakeLists.txt
+++ b/homework4/CMakeLists.txt
@@ -6,3 +6,7 @@ set(CMAKE_CXX_STANDARD 20)
 add_executable(test1 test1.cpp
         BiTree.cpp
         BiTree.h)
+add_executable(test2 test2.cpp
+        BiTree.cpp
+        BiTree.h
+)
diff --git a/homework4/test2.cpp b/homework4/test2.cpp
new file mode 100644
index 0000000..9a7617f
--- /dev/null
+++ b/homework4/test2.cpp
@@ -0,0 +1,44 @@
+/*
+ * 以字符串的形式定义一棵二叉树的先序序列，若字符是‘#’, 表示该二叉树是空树，否则该字符是相应结点的数据元素。读入相应先序序列，建立二叉链式存储结构的二叉树，然后中序遍历该二叉树并输出结点数据。
+ * 输入格式：
+ * 字符串形式的先序序列（即结点的数据类型为单个字符）
+ * 输出格式：
+ * 中序遍历结果
+ * 输入样例：
+ * 在这里给出一组输入。例如：
+ * ABC##DE#G##F###
+ * 输出样例：
+ * CBEGDFA
+ */
+#include <iostream>
+
+#include "BiTree.h"
+using namespace std;
+
+int main()
+{
+    string input;
+    cout << "请输入二叉树的先序序列（如ABC##DE#G##F###）：";
+    cin >> input;
+
+    size_t index = 0;
+    BiTree* root = BiTree::build_from_preorder_string(input, index);
+
+    ostringstream oss;
+    if (root)
+    {
+        root->inOrder(oss);
+        cout << "中序遍历结果：" << oss.str() << endl;;
+        root->destory();
+        delete root;
+    }
+    else
+    {
+        cout << "输入的二叉树为空" << endl;
+    }
+
+    //cout << "该树结构为：" << endl;
+    //cout << root->toString() << endl;
+
+    return 0;
+}