175. Invert Binary Tree "Lintcode by Java"

Description

Invert a binary tree.

Example

  1         1 / \       / 2   3  => 3   2   /         4         4

 

Problem solving: The topic requires to say two tree Saozi right sub-tree to swap, with the return to do very simple:

1 /**2 * Definition of TreeNode:3 * public class TreeNode {4 * public int val;5 * Public TreeNode left and right;6 * Public TreeNode (int val) {7 * This.val = val;8 * This.left = This.right = null;9  *     }Ten  * } One  */ A  -  Public classSolution { -     /** the      * @paramroot:a TreeNode, the root of the binary tree -      * @return: Nothing -      */ -      Public voidinvertbinarytree (TreeNode root) { +         //Write your code here -         if(Root = =NULL) +             return ; ATreeNode left =Root.left; atTreeNode right =Root.right; -Root.left =Right ; -Root.right =Left ; - Invertbinarytree (root.left); - Invertbinarytree (root.right); -     } in}

Non-recursive method:

1  Public classSolution {2      PublicTreeNode inverttree (TreeNode root) {3queue<treenode> q =NewLinkedlist<treenode>();4         if(root!=NULL) Q.offer (root);5          while(!Q.isempty ()) {6TreeNode Curr =Q.poll ();7TreeNode tmp =Curr.right;8Curr.right =Curr.left;9Curr.left =tmp;Ten             if(curr.left!=NULL) Q.offer (curr.left); One             if(curr.right!=NULL) Q.offer (curr.right); A         } -         returnRoot; -     } the}

175. Invert Binary Tree "Lintcode by Java"