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/**
* File: preorder_traversal_i_compact.dart
* Created Time: 2023-08-10
* Author: liuyuxin (gvenusleo@gmail.com)
*/
import '../utils/print_util.dart';
import '../utils/tree_node.dart';
/* 前序遍历:例题一 */
void preOrder(TreeNode? root, List<TreeNode> res) {
if (root == null) {
return;
}
if (root.val == 7) {
// 记录解
res.add(root);
}
preOrder(root.left, res);
preOrder(root.right, res);
}
/* Driver Code */
void main() {
TreeNode? root = listToTree([1, 7, 3, 4, 5, 6, 7]);
print("\n初始化二叉树");
printTree(root);
// 前序遍历
List<TreeNode> res = [];
preOrder(root, res);
print("\n输出所有值为 7 的节点");
print(List.generate(res.length, (i) => res[i].val));
}