?LeetCode刷題實戰(zhàn)144：二叉樹的前序遍歷

/**
?* Definition for a binary tree node.
?* struct TreeNode {
?* int val;
?* TreeNode *left;
?* TreeNode *right;
?* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
?* };
?*/
class?Solution?{
public:
????vector<int> preorderTraversal(TreeNode* root) {
????????
????????vector<int> data = {};
????????vector<int> temp = {};

????????if?(root != NULL)
????????{
????????????data.push_back(root->val);
????????????temp = preorderTraversal(root->left);
????????????data.insert(data.end(),temp.begin(),temp.end());
????????????temp = preorderTraversal(root->right);
????????????data.insert(data.end(),temp.begin(),temp.end());
????????}
????????
????????return?data; 
????}
};