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思路:将root的右子树接在root左子树的最右孩子的右侧,以此交换
/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
void flatten(TreeNode *root) {
if (!root) {
return ;
}
while (root) {
auto tmp = root->left;
if (tmp) {
while (tmp->right) {
tmp = tmp->right;
}
tmp->right = root->right;
root->right = root->left;
root->left = NULL;
}
root = root->right;
}
}
};