Flatten Binary Tree to Linked List
Total Accepted: 68105 Total Submissions: 228885 Difficulty: Medium
Given a binary tree, flatten it to a linked list in-place.
For example,
Given
1 / 2 5 / 3 4 6The flattened tree should look like:
1 2 3 4 5 6
/** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ //中序遍历的变种 class Solution { public: void flatten(TreeNode* root) { if(!root) return; flatten(root->left); TreeNode* tmp_right = root->right; if(root->left){ root->right = root->left; root->left = NULL; while(root->right){ root = root->right; } root->right = tmp_right; } flatten(tmp_right); } };