标签：null nod ems 影响 color link while tps tree
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
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解答
先序遍历同时把节点都堆到左边，因为先序先处理左子树，所以这样操作只是更改叶节点的left而不会对遍历有影响，最后把所有left赋值给right就可以了。
/** * Definition for a binary tree node. * struct TreeNode { * int val; * struct TreeNode *left; * struct TreeNode *right; * }; */ struct TreeNode *pre_node; void DFS(struct TreeNode *root){ if(NULL == root){ return; } if(pre_node != root){ pre_node->left = root; pre_node = root; } DFS(root->left); DFS(root->right); } void flatten(struct TreeNode* root) { pre_node = root; DFS(root); while(root != NULL){ root->right = root->left; root->left = NULL; root = root->right; } }
LeetCode OJ 114. Flatten Binary Tree to Linked List
标签：null nod ems 影响 color link while tps tree
原文地址：http://www.cnblogs.com/YuNanlong/p/6241397.html
