标签:des class blog code java http
Given a binary tree, flatten it to a linked list in-place.
For example,
Given
1 / 2 5 / \ 3 4 6
The flattened tree should look like:
1 2 3 4 5 6
method 1 recursive method:
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public class Solution { public
void flatten(TreeNode root) { if (root != null ){ TreeNode aNode = root.left; if (aNode != null ){ while (aNode.right != null ) aNode = aNode.right; aNode.right = root.right; root.right = root.left; root.left = null ; } root = root.right; flatten(root); } } } |
method2: preorder tree traversal method
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public class Solution { public
void flatten(TreeNode root) { Stack<TreeNode> nodes = new
Stack<TreeNode>(); if (root != null ){ TreeNode currentNode = root; if (root.right != null ) nodes.push(root.right); if (root.left != null ){ nodes.push(root.left); root.left = null ; } while (!nodes.isEmpty()){ TreeNode aNode = nodes.pop(); currentNode.right = aNode; //currentNode.left = null; currentNode = currentNode.right; if (aNode.right != null ) nodes.push(aNode.right); if (aNode.left != null ){ nodes.push(aNode.left); aNode.left = null ; } } } } } |
leetcode--Flatten Binary Tree to Linked List,布布扣,bubuko.com
leetcode--Flatten Binary Tree to Linked List
标签:des class blog code java http
原文地址:http://www.cnblogs.com/averillzheng/p/3785045.html