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hello-algo/codes/c/chapter_backtracking/preorder_traversal_i_compact.c

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1018 B

/**
* 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 = malloc(resSize * sizeof(int));
for (int i = 0; i < resSize; i++) {
vals[i] = res[i]->val;
}
printArray(vals, resSize);
// 释放内存
freeMemoryTree(root);
free(vals);
return 0;
}