public PriorityQueue(T root, Comparison <T> comparison)
{
stack = new StackByResizeableArray <T>();
stack.Push(default);
StackByResizeableArray <int> stack;// where the data is stored
//Left child of stack[i]: stack[2*i]
//Right child of stack[i]: stack[2*i+1]
BinaryHeap(int root)
{
stack = new StackByResizeableArray <int>();
stack.Push(0);
stack.Push(root);
}