144.Binary Tree Preorder Traversal
发布时间:2020-12-14 03:20:30 所属栏目:大数据 来源:网络整理
导读:144 .?Binary Tree Preorder Traversal ////// wrong class Solution { public ListInteger preorderTraversal(TreeNode root) { List Integer result = new ArrayList (); Deque TreeNode stack = new LinkedList (); if (root == null ){ return result; }
144.?Binary Tree Preorder Traversal ////// wrong class Solution { public List<Integer> preorderTraversal(TreeNode root) { List<Integer> result = new ArrayList<>(); Deque<TreeNode> stack = new LinkedList<>(); if(root == null){ return result; } stack.offer(root); while(!stack.isEmpty()){ TreeNode cur = stack.poll(); result.add(cur.val); if(cur.right != null){ stack.offer(cur.right); } if(cur.left != null){ stack.offer(cur.left); } } return result; } } //// this Is okay . Idk why class Solution { public List<Integer> preorderTraversal(TreeNode root) { List<Integer> result = new ArrayList<>(); Deque<TreeNode> stack = new LinkedList<>(); if(root == null){ return result; } stack.push(root); while(!stack.isEmpty()){ TreeNode cur = stack.pop(); result.add(cur.val); if(cur.right != null){ stack.push(cur.right); } if(cur.left != null){ stack.push(cur.left); } } return result; } } ////// correct class Solution { List<Integer> result = new ArrayList<>(); public List<Integer> preorderTraversal(TreeNode root) { if(root == null){ return result; } result.add(root.val); preorderTraversal(root.left); preorderTraversal(root.right); return result; } } ///// wrong,idk why class Solution { public List<Integer> preorderTraversal(TreeNode root) { List<Integer> result = new ArrayList<>(); if(root == null){ return result; } result.add(root.val); preorderTraversal(root.left); preorderTraversal(root.right); return result; } } (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |