Time: 5 ms (6.67%), Space: 10.2 MB (26.15%) - LeetHub

Author: MishkatIT

0144-binary-tree-preorder-traversal/0144-binary-tree-preorder-traversal.cpp

@@ -0,0 +1,27 @@
+/**
+ * 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:
+    vector<int> ans;
+    vector<int> preorderTraversal(TreeNode* root) {
+        dfs(root);
+        return ans;
+    }
+    void dfs(TreeNode* root) {
+        if (!root) return;
+        ans.push_back(root->val);
+        dfs(root->left);
+        dfs(root->right);
+        return;
+    }
+};