update: 102

Author: hijiangtao

README.md

@@ -53,6 +53,7 @@ This is the solutions collection of my LeetCode submissions, most of them are pr
 |91|[Decode Ways](https://leetcode.com/problems/decode-ways/) | [JavaScript](./src/decode-ways/res.js)|Medium|
 |93|[Restore IP Addresses](https://leetcode.com/problems/restore-ip-addresses/) | [JavaScript](./src/restore-ip-addresses/res.js)|Medium|
 |101|[Symmetric Tree](https://leetcode.com/problems/symmetric-tree/) | [JavaScript](./src/symmetric-tree/res.js)|Easy|
+|102|[Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/) | [JavaScript](./src/binary-tree-level-order-traversal/res.js)|Medium|
 |120|[Triangle](https://leetcode.com/problems/triangle/) | [JavaScript](./src/triangle/res.js)|Medium|
 |121|[Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/) | [JavaScript](./src/best-time-to-buy-and-sell-stock/res.js)|Easy|
 |122|[Best Time to Buy and Sell Stock II](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-ii/) | [JavaScript](./src/best-time-to-buy-and-sell-stock-ii/res.js)|Easy|

src/binary-tree-level-order-traversal/res.js

@@ -0,0 +1,36 @@
+/**
+* Definition for a binary tree node.
+* function TreeNode(val) {
+* this.val = val;
+* this.left = this.right = null;
+* }
+*/
+/**
+* @param {TreeNode} root
+* @return {number[][]}
+*/
+var levelOrder = function(root) {
+if (!root) return [];
+
+let queue = [root];
+const res = [];
+
+while(queue.length) {
+const tempQ = [];
+const tempR = [];
+queue.map(e => {
+if (e.val !== undefined) tempR.push(e.val);
+
+if (e.left) {
+tempQ.push(e.left);
+}
+if (e.right) {
+tempQ.push(e.right);
+}
+});
+queue = tempQ;
+res.push(tempR);
+}
+
+return res;
+};