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
刚开始想偷懒想把几个条件混着写，但是写了半天没写出来。后来把4种分开写，很快就完成通过了。注意不是由树变链。
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/** * 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) { flat(root); } TreeNode * flat(TreeNode *root) { TreeNode *tail = root; TreeNode * l = root; TreeNode * r = root; if(root == NULL)return
NULL; if(root->left == NULL && root->right == NULL)return
root; if(root->left != NULL && root->right == NULL) { l= flat(root->left); root->right = root->left; root->left = NULL; return
l; } else
if(root->right!= NULL&&root->left == NULL) { r = flat(root->right); return
r; } else { r = flat(root->right); l= flat(root->left); l->right = root->right; root->right= root->left; root->left =NULL; return
r; } }}; |
Flatten Binary Tree to Linked List,布布扣,bubuko.com
Flatten Binary Tree to Linked List
原文：http://www.cnblogs.com/pengyu2003/p/3611529.html