在C中使用递归DFS返回节点本身

#include <stdio.h>

// 定义节点结构
struct Node {
    int data;
    struct Node* left;
    struct Node* right;
};

// 创建新节点
struct Node* createNode(int data) {
    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
    if (newNode == NULL) {
        printf("内存分配失败\n");
        exit(1);
    }
    newNode->data = data;
    newNode->left = NULL;
    newNode->right = NULL;
    return newNode;
}

// 递归DFS返回节点本身
struct Node* dfs(struct Node* node, int target) {
    if (node == NULL) {
        return NULL;
    }
    if (node->data == target) {
        return node;
    }
    struct Node* leftResult = dfs(node->left, target);
    if (leftResult != NULL) {
        return leftResult;
    }
    struct Node* rightResult = dfs(node->right, target);
    if (rightResult != NULL) {
        return rightResult;
    }
    return NULL;
}

int main() {
    // 构建二叉树
    struct Node* 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(6);
    root->right->right = createNode(7);

    // 在二叉树中查找节点值为5的节点
    struct Node* result = dfs(root, 5);
    if (result != NULL) {
        printf("找到了节点 %d\n", result->data);
    } else {
        printf("未找到目标节点\n");
    }

    return 0;
}