题目描述
操作给定的二叉树,将其变换为源二叉树的镜像。
输入描述:
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
思路:
- 判断根节点的正确与否
- 分别判断左右节点存在?
- 左右互换(用临时变量)
- 开始递归
/*
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};*/
class Solution {
public:
void Mirror(TreeNode *pRoot) {
if(pRoot==NULL)
return;
if(pRoot->left!=NULL||pRoot->right!=NULL)
{
struct TreeNode* tmp=pRoot->left;
pRoot->left=pRoot->right;
pRoot->right=tmp;
if(pRoot->left!=NULL)
Mirror(pRoot->left);
if(pRoot->right!=NULL)
Mirror(pRoot->right);
}
}
};
JAVA解法
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public TreeNode mirrorTree(TreeNode root) {
if(root == null){
return null;
}
TreeNode res = new TreeNode(root.val);
res.left = mirrorTree(root.right);
res.right = mirrorTree(root.left);
return res;
}
}