Add solution #105

Author: JoshCrozier

README.md

@@ -109,6 +109,7 @@
 102|[Binary Tree Level Order Traversal](./0102-binary-tree-level-order-traversal.js)|Medium|
 103|[Binary Tree Zigzag Level Order Traversal](./0103-binary-tree-zigzag-level-order-traversal.js)|Medium|
 104|[Maximum Depth of Binary Tree](./0104-maximum-depth-of-binary-tree.js)|Easy|
+105|[Construct Binary Tree from Preorder and Inorder Traversal](./0105-construct-binary-tree-from-preorder-and-inorder-traversal.js)|Medium|
 108|[Convert Sorted Array to Binary Search Tree](./0108-convert-sorted-array-to-binary-search-tree.js)|Easy|
 110|[Balanced Binary Tree](./0110-balanced-binary-tree.js)|Easy|
 111|[Minimum Depth of Binary Tree](./0111-minimum-depth-of-binary-tree.js)|Easy|

solutions/0105-construct-binary-tree-from-preorder-and-inorder-traversal.js

@@ -0,0 +1,34 @@
+/**
+ * 105. Construct Binary Tree from Preorder and Inorder Traversal
+ * https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/
+ * Difficulty: Medium
+ *
+ * Given two integer arrays preorder and inorder where preorder is the preorder traversal of a
+ * binary tree and inorder is the inorder traversal of the same tree, construct and return the
+ * 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 {number[]} preorder
+ * @param {number[]} inorder
+ * @return {TreeNode}
+ */
+var buildTree = function(preorder, inorder) {
+  if (!preorder.length || !inorder.length) return null;
+
+  const root = new TreeNode(preorder[0]);
+  const mid = inorder.indexOf(preorder[0]);
+
+  root.left = buildTree(preorder.slice(1, mid + 1), inorder.slice(0, mid));
+  root.right = buildTree(preorder.slice(mid + 1), inorder.slice(mid + 1));
+
+  return root;
+};