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; } } };