add binary-tree-right-side-view problem

Author: sagivo

README.md

@@ -18,6 +18,7 @@ This is my way of saying - change your interview style. There are lots of smart
 | [Coin change](https://leetcode.com/problems/coin-change/description/) | [click](https://github.com/sagivo/algorithms/blob/master/src/coin-change.rb) |
 | [Decode Strings](https://leetcode.com/problems/decode-string/description/) | [click](https://github.com/sagivo/algorithms/blob/master/src/decode_string.rb) |
 | [Wiggle Subsequence](https://leetcode.com/problems/wiggle-subsequence/description/) | [click](https://github.com/sagivo/algorithms/blob/master/src/wiggle_subsequence.rb) |
+| [Binary Tree Side View](https://leetcode.com/problems/binary-tree-right-side-view/description/) | [click](https://github.com/sagivo/algorithms/blob/master/src/binary_tree_side_view.rb) |
 | [Unix path](https://leetcode.com/problems/simplify-path/description/) | [click](https://github.com/sagivo/algorithms/blob/master/src/simplify_path.rb) |
 | [Array Product](https://leetcode.com/problems/product-of-array-except-self/description/) | [click](https://github.com/sagivo/algorithms/blob/master/src/product-of-array.rb) |
 | [Top K Frequent Elements](https://leetcode.com/problems/top-k-frequent-elements/description/) | [click](https://github.com/sagivo/algorithms/blob/master/src/top-k-elements.rb) |

src/binary_tree_side_view.rb

@@ -0,0 +1,31 @@
+# Definition for a binary tree node.
+# class TreeNode
+# attr_accessor :val, :left, :right
+# def initialize(val)
+# @val = val
+# @left, @right = nil, nil
+# end
+# end
+
+# @param {TreeNode} root
+# @return {Integer[]}
+def right_side_view(root)
+ q = [[root]]
+ res = []
+ while q.any?
+ nodes = q.shift
+ new_list = []
+ last = nil
+ nodes.each do |n| 
+ if n
+ new_list += [n.left,n.right] 
+ last = n
+ end
+ end
+ q << new_list if new_list.any?
+ res << last.val if last
+ end
+ return res
+end
+
+# p right_side_view([1,2,3,null,5,null,4]) # => [1,3,4]