Invert a binary tree.
4 / \ 2 7 / \ / \ 1 3 6 9to
4 / \ 7 2 / \ / \ 9 6 3 1二叉树反转,采用递归的方式。
- 输入结点为空时,返回为空;
- 将右子树反转,left指向右子树;将左子树反转,将right指向左子树。
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
TreeNode* invertTree(TreeNode* root) {
if(root==NULL)
return NULL;
TreeNode* p=root->left;
root->left=invertTree(root->right);
root->right=invertTree(p);
return root;
}
};