Merge pull request #3603 from aadil42/patch-120

Create 0606-construct-string-from-binary-tree.js

Author: Ykhan799

javascript/0606-construct-string-from-binary-tree.js

@@ -0,0 +1,35 @@
+/**
+ * InOrder Traversal 
+ * Time O(n) | Space O(n)
+ * https://leetcode.com/problems/construct-string-from-binary-tree/
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {string}
+ */
+var tree2str = function(root) {
+    return dfs(root, []).join("");
+};
+
+const dfs = (node, strArr) => {
+    if (!node) return;
+
+    strArr.push(node.val);
+
+    if (node.right || node.left) strArr.push("(");
+    dfs(node.left, strArr);
+    if (node.right || node.left) strArr.push(")");
+
+    // right tree
+    if (node.right) strArr.push("(");
+    dfs(node.right, strArr);
+    if (node.right) strArr.push(")");
+
+    return strArr;
+}