{"id":10886,"date":"2019-01-14T02:44:59","date_gmt":"2019-01-14T02:44:59","guid":{"rendered":"http:\/\/www.softwareeverydayblog.com\/?p=10886"},"modified":"2019-01-14T02:45:41","modified_gmt":"2019-01-14T02:45:41","slug":"leetcode-binary-tree-right-side-view","status":"publish","type":"post","link":"https:\/\/www.softwareeverydayblog.com\/?p=10886","title":{"rendered":"[Leetcode] Binary Tree Right Side View"},"content":{"rendered":"<p>[<a href=\"https:\/\/leetcode.com\/problems\/binary-tree-right-side-view\/description\/\" rel=\"noopener\" target=\"_blank\">Problem Link<\/a>]<\/p>\n<p>Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom.<\/p>\n<p><strong>Example<\/strong>:<\/p>\n<pre lang=\"text\">\r\nInput: [1,2,3,null,5,null,4]\r\nOutput: [1, 3, 4]\r\nExplanation:\r\n\r\n   1            <---\r\n \/   \\\r\n2     3         <---\r\n \\     \\\r\n  5     4       <---\r\n<\/pre>\n<ul>\n<li>Perform a breath first traversal of the tree also called a <a href=\"https:\/\/www.geeksforgeeks.org\/level-order-tree-traversal\/\" rel=\"noopener\" target=\"_blank\">level order traversal<\/a>.<\/li>\n<li>Before you start processing any level, add the last node from your Q\/list to the return list. That's the node the user would see from the right side.<\/li>\n<\/ul>\n<pre lang=\"java\">\r\n\/**\r\n * Definition for a binary tree node.\r\n * public class TreeNode {\r\n *     int val;\r\n *     TreeNode left;\r\n *     TreeNode right;\r\n *     TreeNode(int x) { val = x; }\r\n * }\r\n *\/\r\nclass Solution {\r\n    public List<Integer> rightSideView(TreeNode root) {\r\n        List<Integer> ret = new ArrayList<Integer>();\r\n        LinkedList<TreeNode> q = new LinkedList<TreeNode>();\r\n        if ( root != null )\r\n            q.add(root);\r\n        while ( q.size() > 0 ) {\r\n            int levelSize = q.size();\r\n            ret.add(q.getLast().val);\r\n            for ( int i = 0 ; i < levelSize ; i++ ) {\r\n                TreeNode curr = q.remove(0);\r\n                if ( curr.left != null )\r\n                    q.add(curr.left);\r\n                if ( curr.right != null )\r\n                    q.add(curr.right);\r\n            }\r\n        }\r\n        return ret;\r\n    }\r\n}\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>[Problem Link] Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom. Example: Input: [1,2,3,null,5,null,4] Output: [1, 3, 4] Explanation: 1<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-10886","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/www.softwareeverydayblog.com\/index.php?rest_route=\/wp\/v2\/posts\/10886","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.softwareeverydayblog.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.softwareeverydayblog.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.softwareeverydayblog.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.softwareeverydayblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=10886"}],"version-history":[{"count":3,"href":"https:\/\/www.softwareeverydayblog.com\/index.php?rest_route=\/wp\/v2\/posts\/10886\/revisions"}],"predecessor-version":[{"id":10889,"href":"https:\/\/www.softwareeverydayblog.com\/index.php?rest_route=\/wp\/v2\/posts\/10886\/revisions\/10889"}],"wp:attachment":[{"href":"https:\/\/www.softwareeverydayblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10886"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.softwareeverydayblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10886"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.softwareeverydayblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10886"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}