Add solution #257

Author: JoshCrozier

README.md

@@ -206,6 +206,7 @@
 237|[Delete Node in a Linked List](./0237-delete-node-in-a-linked-list.js)|Easy|
 238|[Product of Array Except Self](./0238-product-of-array-except-self.js)|Medium|
 242|[Valid Anagram](./0242-valid-anagram.js)|Easy|
+257|[Binary Tree Paths](./0257-binary-tree-paths.js)|Easy|
 258|[Add Digits](./0258-add-digits.js)|Easy|
 260|[Single Number III](./0260-single-number-iii.js)|Medium|
 263|[Ugly Number](./0263-ugly-number.js)|Easy|

solutions/0257-binary-tree-paths.js

@@ -0,0 +1,37 @@
+/**
+ * 257. Binary Tree Paths
+ * https://leetcode.com/problems/binary-tree-paths/
+ * Difficulty: Easy
+ *
+ * Given the root of a binary tree, return all root-to-leaf paths in any order.
+ *
+ * A leaf is a node with no children.
+ */
+
+/**
+ * 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 binaryTreePaths = function(root) {
+  return tranverse(root);
+};
+
+function tranverse(node, path = [], result = []) {
+  if (!node) return;
+  path.push(node.val.toString());
+  if (!node.left && !node.right) {
+    result.push(path.join('->'));
+  } else {
+    tranverse(node.left, path.slice(), result);
+    tranverse(node.right, path.slice(), result);
+  }
+  return result;
+}