力扣144 递归实现二叉树前序遍历 - 达拉崩吧01 - 沸点 - 掘金

2年前

#每日一题# 力扣144 递归实现二叉树前序遍历
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
void preorder(TreeNode* root,vector<int>& res)//这里要用地址传递
{
if(root == nullptr)
return;
res.push_back(root->val);
preorder(root->left,res);
preorder(root->right,res);
}
vector<int> preorderTraversal(TreeNode* root) {
vector<int> res;
preorder(root,res);
return res;

}

};

展开