Add solution #429

Author: JoshCrozier

README.md

@@ -340,6 +340,7 @@
 423|[Reconstruct Original Digits from English](./0423-reconstruct-original-digits-from-english.js)|Medium|
 424|[Longest Repeating Character Replacement](./0424-longest-repeating-character-replacement.js)|Medium|
 427|[Construct Quad Tree](./0427-construct-quad-tree.js)|Medium|
+429|[N-ary Tree Level Order Traversal](./0429-n-ary-tree-level-order-traversal.js)|Medium|
 434|[Number of Segments in a String](./0434-number-of-segments-in-a-string.js)|Easy|
 435|[Non-overlapping Intervals](./0435-non-overlapping-intervals.js)|Medium|
 437|[Path Sum III](./0437-path-sum-iii.js)|Medium|

solutions/0429-n-ary-tree-level-order-traversal.js

@@ -0,0 +1,41 @@
+/**
+ * 429. N-ary Tree Level Order Traversal
+ * https://leetcode.com/problems/n-ary-tree-level-order-traversal/
+ * Difficulty: Medium
+ *
+ * Given an n-ary tree, return the level order traversal of its nodes' values.
+ *
+ * Nary-Tree input serialization is represented in their level order traversal, each group of
+ * children is separated by the null value.
+ */
+
+/**
+ * // Definition for a _Node.
+ * function _Node(val,children) {
+ *    this.val = val;
+ *    this.children = children;
+ * };
+ */
+
+/**
+ * @param {_Node|null} root
+ * @return {number[][]}
+ */
+var levelOrder = function(root) {
+  if (!root) return [];
+
+  const result = [];
+  const queue = [root];
+
+  while (queue.length) {
+    const [level, current] = [queue.length, []];
+    for (let i = 0; i < level; i++) {
+      const node = queue.shift();
+      current.push(node.val);
+      queue.push(...node.children);
+    }
+    result.push(current);
+  }
+
+  return result;
+};