统计C语言中二叉树的出现次数

#include <stdio.h>
#include <stdlib.h>

// 定义二叉树节点结构
struct TreeNode {
    int data;
    struct TreeNode* left;
    struct TreeNode* right;
};

// 创建新的二叉树节点
struct TreeNode* createNode(int data) {
    struct TreeNode* newNode = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    newNode->data = data;
    newNode->left = NULL;
    newNode->right = NULL;
    return newNode;
}

// 统计二叉树的出现次数
int countOccurrences(struct TreeNode* root, int target) {
    if (root == NULL) {
        return 0;
    }
    
    int count = 0;
    if (root->data == target) {
        count++;
    }
    
    count += countOccurrences(root->left, target);
    count += countOccurrences(root->right, target);
    
    return count;
}

int main() {
    // 创建一个二叉树
    struct TreeNode* root = createNode(1);
    root->left = createNode(2);
    root->right = createNode(3);
    root->left->left = createNode(4);
    root->left->right = createNode(5);
    root->right->left = createNode(2);
    root->right->right = createNode(7);
    
    int target = 2;
    int occurrences = countOccurrences(root, target);
    
    printf("二叉树中出现 %d 的次数为 %d\n", target, occurrences);
    
    return 0;
}