Given a binary search tree and the lowest and highest boundaries as L
and R
, trim the tree so that all its elements lies in [L, R]
(R >= L). You might need to change the root of the tree, so the result should return the new root of the trimmed binary search tree.
Example 1:
Input: 1 / 0 2 L = 1 R = 2 Output: 1 2
Example 2:
Input: 3 / 0 4 2 / 1 L = 1 R = 3 Output: 3 / 2 / 1
class Solution { public: TreeNode* trimBST(TreeNode* root, int L, int R) { if (root == nullptr) return 0; if (root->val < L) return trimBST(root->right, L, R); else if (root->val > R) return trimBST(root->left, L, R); else { root->left = trimBST(root->left, L, R); root->right = trimBST(root->right, L, R); return root; } } };