题目描述
操作给定的二叉树,将其变换为源二叉树的镜像。
二叉树的镜像定义:
源二叉树
8
/ \
6 10
/ \ / \
5 7 9 11
镜像二叉树
8
/ \
10 6
/ \ / \
11 9 7 5
递归版
/**
public class TreeNode {
int val = 0;
TreeNode left = null;
TreeNode right = null;
public TreeNode(int val) {
this.val = val;
}
}
*/
import java.util.*;
public class Solution {
public void Mirror(TreeNode root) {
if(root==null)
return ;
if(root.left==null && root.right==null)
return;
TreeNode temp = root.left;
root.left = root.right;
root.right = temp;
if(root.left!=null)
Mirror(root.left);
if(root.right!=null)
Mirror(root.right);
}
}
非递归版
public class Solution {
public void Mirror(TreeNode root) {
if(root==null)
return ;
Stack<TreeNode> stack = new Stack<>();
stack.push(root);
while(!stack.isEmpty()){
TreeNode node = stack.pop();
if(node.left!=null || node.right!=null){
TreeNode temp = node.left;
node.left = node.right;
node.right = temp;
}
if(node.left!=null)
stack.push(node.left);
if(node.right!=null)
stack.push(node.right);
}
}
}