init

24/11/tree.c

@@ -0,0 +1,219 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+typedef struct TreeNode
+{
+    int val;
+    struct TreeNode *left;
+    struct TreeNode *right;
+} TreeNode;
+
+typedef struct StackNode
+{
+    TreeNode *treeNode;
+    struct StackNode *next;
+} StackNode;
+
+typedef struct Stack
+{
+    StackNode *top;
+} Stack;
+
+void push(Stack *stack, TreeNode *treeNode)
+{
+    StackNode *newNode = (StackNode *)malloc(sizeof(StackNode));
+    newNode->treeNode = treeNode;
+    newNode->next = stack->top;
+    stack->top = newNode;
+}
+
+TreeNode *pop(Stack *stack)
+{
+    if (stack->top == NULL)
+    {
+        return NULL;
+    }
+    StackNode *temp = stack->top;
+    TreeNode *treeNode = temp->treeNode;
+    stack->top = stack->top->next;
+    free(temp);
+    return treeNode;
+}
+
+int isEmpty(Stack *stack)
+{
+    return stack->top == NULL;
+}
+
+void preorder(TreeNode *root)
+{
+    if (root == NULL)
+    {
+        return;
+    }
+
+    Stack stack = {NULL};
+    TreeNode *p = root;
+    while (p != NULL || !isEmpty(&stack))
+    {
+        while (p != NULL)
+        {
+            printf("%d ", p->val);
+            push(&stack, p);
+            p = p->left;
+        }
+        p = pop(&stack);
+        p = p->right;
+    }
+}
+
+void inorder(TreeNode *root)
+{
+    if (root == NULL)
+    {
+        return;
+    }
+
+    Stack stack = {NULL};
+    TreeNode *p = root;
+    while (p != NULL || !isEmpty(&stack))
+    {
+        while (p != NULL)
+        {
+            push(&stack, p);
+            p = p->left;
+        }
+        p = pop(&stack);
+        printf("%d ", p->val);
+        p = p->right;
+    }
+}
+
+void postorder(TreeNode *root)
+{
+    if (root == NULL)
+    {
+        return;
+    }
+
+    Stack stack = {NULL};
+    TreeNode *p = root;
+    TreeNode *pre = NULL;
+    do
+    {
+        while (p != NULL)
+        {
+            push(&stack, p);
+            p = p->left;
+        }
+        p = pop(&stack);
+        if (p->right == NULL || p->right == pre)
+        {
+            printf("%d ", p->val);
+            pre = p;
+            p = NULL;
+        }
+        else
+        {
+            push(&stack, p);
+            p = p->right;
+        }
+    } while (!isEmpty(&stack));
+}
+
+void Postorderd(TreeNode *root)
+{
+    if (root == NULL)
+    {
+        return;
+    }
+    Postorderd(root->left);
+    Postorderd(root->right);
+    printf("%d ", root->val);
+}
+
+
+TreeNode* createTreeNode(int val) {
+    TreeNode* node = (TreeNode*)malloc(sizeof(TreeNode));
+    node->val = val;
+    node->left = NULL;
+    node->right = NULL;
+    return node;
+}
+
+TreeNode* generateCompleteBinaryTree(int nodeCount) {
+    if (nodeCount <= 0) {
+        return NULL;
+    }
+
+    srand(time(NULL));
+    TreeNode** nodes = (TreeNode**)malloc(nodeCount * sizeof(TreeNode*));
+    for (int i = 0; i < nodeCount; i++) {
+        nodes[i] = createTreeNode(rand() % 100 + 1);
+    }
+
+    for (int i = 0; i < nodeCount; i++) {
+        if (2 * i + 1 < nodeCount) {
+            nodes[i]->left = nodes[2 * i + 1];
+        }
+        if (2 * i + 2 < nodeCount) {
+            nodes[i]->right = nodes[2 * i + 2];
+        }
+    }
+
+    TreeNode* root = nodes[0];
+    free(nodes);
+    return root;
+}
+
+void printTreeStructure(TreeNode* root) {
+    if (root == NULL) {
+        return;
+    }
+    printf("%d ", root->val);
+    if (root->left != NULL || root->right != NULL) {
+        printf("(");
+        printTreeStructure(root->left);
+        printf(", ");
+        printTreeStructure(root->right);
+        printf(")");
+    }
+}
+
+/*
+生成的二叉树结构如下：
+
+           2
+         /   \
+       /       \
+      4         7
+    /   \      / \
+   9     11  22  44
+  / \   /
+ 66 88 99
+
+*/
+TreeNode* generateSpecificBinaryTree() 
+{
+    int values[] = {2, 4, 7, 9, 11, 22, 44, 66, 88, 99};
+    int nodeCount = sizeof(values) / sizeof(values[0]);
+
+    TreeNode** nodes = (TreeNode**)malloc(nodeCount * sizeof(TreeNode*));
+    for (int i = 0; i < nodeCount; i++) {
+        nodes[i] = createTreeNode(values[i]);
+    }
+
+    for (int i = 0; i < nodeCount; i++) {
+        if (2 * i + 1 < nodeCount) {
+            nodes[i]->left = nodes[2 * i + 1];
+        }
+        if (2 * i + 2 < nodeCount) {
+            nodes[i]->right = nodes[2 * i + 2];
+        }
+    }
+
+    TreeNode* root = nodes[0];
+    free(nodes);
+    return root;
+}