Created
April 2, 2017 19:28
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bool remove(T d) { | |
if (!contains(d)) | |
return false; | |
removeHelper(root_, d); | |
return true; | |
} | |
TreeNode<T>* removeHelper(TreeNode<T> *n, T d) { | |
if (d < n->data_) { | |
n->left_ = removeHelper(n->left_, d); | |
} else if (d > n->data_) { | |
n->right_ = removeHelper(n->right_, d); | |
} else { | |
if (n->left_ == nullptr && n->right_ == nullptr) { // no children | |
delete n; | |
return nullptr; | |
} else if (n->left_ == nullptr) { // has right child | |
TreeNode<T> *rightchild = n->right_; | |
delete n; | |
return rightchild; | |
} else if (n->right_ == nullptr) { // has left child | |
TreeNode<T> *leftchild = n->left_; | |
delete n; | |
return leftchild; | |
} else { // 2 children | |
TreeNode<T> *predecessor = findPredecessor(n); | |
std::swap(n->data_, predecessor->data_); | |
n->left_ = removeHelper(n->left_, d); | |
} | |
} | |
return n; | |
} | |
TreeNode<T>* findPredecessor(TreeNode<T> *n) { | |
TreeNode<T> *p = n->left_; | |
while (p->right_ != nullptr) | |
p = p->right_; | |
return p; | |
} |
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