[leetcode]Binary Tree Right Side View

Build on top of the problem "Binary Tree Level Order Traversal II" without reversing the result, and only use the last element of each list

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public class Solution { public List<Integer> rightSideView(TreeNode root) { levelOrderBottom(root); List<Integer> list = new ArrayList<Integer>(); for(int i = 0; i < result.size(); i++){ List<Integer> temp = result.get(i); list.add(temp.get(temp.size()-1)); } return list; } List<List<Integer>> result = new ArrayList<List<Integer>>(); public void levelOrderBottom(TreeNode root) { dfsLevel(root, 0); } private void dfsLevel(TreeNode root, int level){ if (root == null) return; if (result.size() < level+1) result.add(new ArrayList<Integer>()); result.get(level).add(root.val); dfsLevel(root.left, level+1); dfsLevel(root.right, level+1); } }