// CookieJar - A contestant's algorithm toolbox
// Copyright (c) 2013 Peter Szilagyi. All rights reserved.
//
// CookieJar is dual licensed: use of this source code is governed by a BSD
// license that can be found in the LICENSE file. Alternatively, the CookieJar
// toolbox may be used in accordance with the terms and conditions contained
// in a signed written agreement between you and the author(s).

// Package set implements simple present/not data structure supporting arbitrary
// types (even a mixture).
//
// Internally it uses a simple map assigning zero-byte struct{}s to keys.
package set

// Set data structure.
type Set struct {
	data map[interface{}]struct{}
}

// Creates a new empty set.
func New() *Set {
	return &Set{make(map[interface{}]struct{})}
}

// Inserts an element into the set.
func (s *Set) Insert(val interface{}) {
	s.data[val] = struct{}{}
}

// Removes an element from the set. If none was present, nothing is done.
func (s *Set) Remove(val interface{}) {
	delete(s.data, val)
}

// Returns the number of elements in the set.
func (s *Set) Size() int {
	return len(s.data)
}

// Checks whether an element is inside the set.
func (s *Set) Exists(val interface{}) bool {
	_, ok := s.data[val]
	return ok
}

// Executes a function for every element in the set.
func (s *Set) Do(f func(interface{})) {
	for val, _ := range s.data {
		f(val)
	}
}

// Clears the contents of a set.
func (s *Set) Reset() {
	*s = *New()
}