/** * File: preorder_traversal_i_compact.c * Created Time: 2023-05-10 * Author: Gonglja (glj0@outlook.com) */ #include "../utils/common.h" // 假设结果长度不超过 100 #define MAX_SIZE 100 TreeNode *res[MAX_SIZE]; int resSize = 0; /* 前序遍历:例题一 */ void preOrder(TreeNode *root) { if (root == NULL) { return; } if (root->val == 7) { // 记录解 res[resSize++] = root; } preOrder(root->left); preOrder(root->right); } /* Driver Code */ int main() { int arr[] = {1, 7, 3, 4, 5, 6, 7}; TreeNode *root = arrayToTree(arr, sizeof(arr) / sizeof(arr[0])); printf("\n初始化二叉树\n"); printTree(root); // 前序遍历 preOrder(root); printf("\n输出所有值为 7 的节点\n"); int vals[resSize]; for (int i = 0; i < resSize; i++) { vals[i] = res[i]->val; } printArray(vals, resSize); // 释放内存 freeMemoryTree(root); return 0; }