void find_left_most(TreeNode *root, vector<int> &path)
{
if(!root || (root->left == NULL && root->right == NULL))
return;
path.push_back(root->val);
if(root->left)
find_left_most(root->left, path);
else if(root->right)
find_left_most(root->right, path);
}
bool BinaryTree<T>::isOrdered(const Node * sub_root) const
{
// base case:
if( sub_root == NULL )
{
return true;
}
// recursive case:
else
{
if( sub_root->left != NULL )
{
Node *temp = find_right_most(sub_root);
if( temp->elem > sub_root->elem )
{
return false;
}
}
if( sub_root->right != NULL )
{
Node *temp = find_left_most(sub_root);
if( temp->elem < sub_root->elem )
{
return false;
}
}
return isOrdered(sub_root->left)&&isOrdered(sub_root->right);
}
}
vector<int> boundaryOfBinaryTree(TreeNode * root) {
// write your code here
if(!root)
return {};
else if(root->left == NULL && root->right == NULL)
return {root->val};
vector<int> ans;
ans.push_back(root->val);
TreeNode* node;
// Find left boundary
node = root->left;
vector<int> left_boundary;
find_left_most(node, left_boundary);
// Find all leaves
vector<int> leaves;
find_leaves(root, leaves);
// Find right boundary, reverse it
node = root->right;
vector<int> right_boundary;
find_right_most(node, right_boundary);
reverse(right_boundary.begin(), right_boundary.end());
for(auto x: left_boundary)
ans.push_back(x);
for(auto x: leaves)
ans.push_back(x);
for(auto x: right_boundary)
ans.push_back(x);
return ans;
}
