1// Copyright 2017 Google Inc. 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15// Package sets provides sets for storing collections of unique elements. 16package sets 17 18// present is an empty struct used as the "value" in the map[int], since empty 19// structs consume zero bytes (unlike one unnecessary byte per bool). 20type present struct{} 21