TreeNode* trimBST(TreeNode* root, int L, int R) {
if (!root) {
return root;
}
//for the nodes which are outside L,R, remove them from the tree
if (root->val < L) return trimBST(root->right,L,R);
if (root->val > R) return trimBST(root->left,L,R);
//for the nodes inside L,R modify their left and right values to be inside L,R
root->left = trimBST(root->left,L,R);
root->right = trimBST(root->right,L,R);
return root;
}
TreeNode* trimBST(TreeNode* root, int L, int R) {
if(root == NULL)
return NULL;
if(root->val < L)
return trimBST(root->right, L, R);
else if(root->val > R)
return trimBST(root->left, L, R);
root->left = trimBST(root->left, L, root->val);
root->right = trimBST(root->right, root->val, R);
return root;
}
TreeNode* trimBST(TreeNode* root, int L, int R) {
if (!root) {
return nullptr;
}
if (root->val < L) {
return trimBST(root->right, L, R);
}
if (root->val > R) {
return trimBST(root->left, L, R);
}
root->left = trimBST(root->left, L, R);
root->right = trimBST(root->right, L, R);
return root;
}
