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leetcode level order traversal

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Lines changed: 2 additions & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -209,7 +209,7 @@ solution of many challenges of [Leetcode](https://leetcode.com/), [Exercism](htt`
`209`	`209`	`8. [Balanced Binary tree](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/leetcode/grind75/balanced_binary_tree.rb)`
`210`	`210`	`9. [Symmetric Tree](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/leetcode/grind75/symmetric_tree.rb)`
`211`	`211`	`10. [Subtree of Another Tree](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/leetcode/grind75/subtree_of_another_tree.rb)`
`212`		`-`
	`212`	`+11.[Binary Tree Level order Traversal](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/leetcode/binary_tree_level_order_traversal.rb)`
`213`	`213`
`214`	`214`	`<a name="bst"/>`
`215`	`215`
`@@ -308,6 +308,7 @@ solution of many challenges of [Leetcode](https://leetcode.com/), [Exercism](htt`
`308`	`308`
`309`	`309`	`## [LeetCode](https://leetcode.com/problems)`
`310`	`310`	`1. [Insert Delete GetRandom in O(1)](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/leetcode/insert_delete_get_random_o1.rb)`
	`311`	`+2. [Binary Tree Level order Traversal](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/leetcode/binary_tree_level_order_traversal.rb)`
`311`	`312`
`312`	`313`	`<a name="grind-75"/>`
`313`	`314`

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`@@ -0,0 +1,37 @@`
	`1`	`+=begin`
	`2`	`+Problem: https://leetcode.com/problems/binary-tree-level-order-traversal/description/`
	`3`	`+Given the root of a binary tree, return the level order traversal of its nodes' values. (i.e., from left to right, level by level).`
	`4`	`+=end`
	`5`	`+`
	`6`	`+#Solution (Using BFS/Queue)`
	`7`	`+`
	`8`	`+# Definition for a binary tree node.`
	`9`	`+# class TreeNode`
	`10`	`+# attr_accessor :val, :left, :right`
	`11`	`+# def initialize(val = 0, left = nil, right = nil)`
	`12`	`+# @val = val`
	`13`	`+# @left = left`
	`14`	`+# @right = right`
	`15`	`+# end`
	`16`	`+# end`
	`17`	`+# @param {TreeNode} root`
	`18`	`+# @return {Integer[][]}`
	`19`	`+def level_order(root)`
	`20`	`+ val_list = []`
	`21`	`+ return [] if root.nil?`
	`22`	`+ queue = [root] # Queue.new can be used instead of List for efficiency of insertion`
	`23`	`+`
	`24`	`+ until queue.empty?`
	`25`	`+ level = []`
	`26`	`+ size = queue.length`
	`27`	`+`
	`28`	`+ size.times do`
	`29`	`+ node = queue.pop()`
	`30`	`+ level.append(node.val)`
	`31`	`+ queue.unshift(node.left) if node.left`
	`32`	`+ queue.unshift(node.right) if node.right`
	`33`	`+ end`
	`34`	`+ val_list.append(level)`
	`35`	`+ end`
	`36`	`+ val_list`
	`37`	`+end`

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