Problem: 897. Increasing Order Search Tree 递增顺序搜索树
耗时100%，中序遍历的同时build题意中的二叉树
Code
/** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode() : val(0), left(nullptr), right(nullptr) {} * TreeNode(int x) : val(x), left(nullptr), right(nullptr) {} * TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {} * }; */ class Solution { public: TreeNode* te = new TreeNode(-1), parent; void inorder(TreeNode* root) { if(root==nullptr) return; inorder(root->left); if(te->val < 0) { te->val = root->val; } else if(te->right == nullptr) { te->right = new TreeNode(root->val); te = te->right; } inorder(root->right); } TreeNode* increasingBST(TreeNode* root) { TreeNode* ret = te; inorder(root); return ret; } };
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