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// run
// Copyright 2021 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
"fmt"
"sort"
)
// _Equal reports whether two slices are equal: the same length and all
// elements equal. All floating point NaNs are considered equal.
func _SliceEqual[Elem comparable](s1, s2 []Elem) bool {
if len(s1) != len(s2) {
return false
}
for i, v1 := range s1 {
v2 := s2[i]
if v1 != v2 {
isNaN := func(f Elem) bool { return f != f }
if !isNaN(v1) || !isNaN(v2) {
return false
}
}
}
return true
}
// A _Set is a set of elements of some type.
type _Set[Elem comparable] struct {
m map[Elem]struct{}
}
// _Make makes a new set.
func _Make[Elem comparable]() _Set[Elem] {
return _Set[Elem]{m: make(map[Elem]struct{})}
}
// Add adds an element to a set.
func (s _Set[Elem]) Add(v Elem) {
s.m[v] = struct{}{}
}
// Delete removes an element from a set. If the element is not present
// in the set, this does nothing.
func (s _Set[Elem]) Delete(v Elem) {
delete(s.m, v)
}
// Contains reports whether v is in the set.
func (s _Set[Elem]) Contains(v Elem) bool {
_, ok := s.m[v]
return ok
}
// Len returns the number of elements in the set.
func (s _Set[Elem]) Len() int {
return len(s.m)
}
// Values returns the values in the set.
// The values will be in an indeterminate order.
func (s _Set[Elem]) Values() []Elem {
r := make([]Elem, 0, len(s.m))
for v := range s.m {
r = append(r, v)
}
return r
}
// _Equal reports whether two sets contain the same elements.
func _Equal[Elem comparable](s1, s2 _Set[Elem]) bool {
if len(s1.m) != len(s2.m) {
return false
}
for v1 := range s1.m {
if !s2.Contains(v1) {
return false
}
}
return true
}
// Copy returns a copy of s.
func (s _Set[Elem]) Copy() _Set[Elem] {
r := _Set[Elem]{m: make(map[Elem]struct{}, len(s.m))}
for v := range s.m {
r.m[v] = struct{}{}
}
return r
}
// AddSet adds all the elements of s2 to s.
func (s _Set[Elem]) AddSet(s2 _Set[Elem]) {
for v := range s2.m {
s.m[v] = struct{}{}
}
}
// SubSet removes all elements in s2 from s.
// Values in s2 that are not in s are ignored.
func (s _Set[Elem]) SubSet(s2 _Set[Elem]) {
for v := range s2.m {
delete(s.m, v)
}
}
// Intersect removes all elements from s that are not present in s2.
// Values in s2 that are not in s are ignored.
func (s _Set[Elem]) Intersect(s2 _Set[Elem]) {
for v := range s.m {
if !s2.Contains(v) {
delete(s.m, v)
}
}
}
// Iterate calls f on every element in the set.
func (s _Set[Elem]) Iterate(f func(Elem)) {
for v := range s.m {
f(v)
}
}
// Filter deletes any elements from s for which f returns false.
func (s _Set[Elem]) Filter(f func(Elem) bool) {
for v := range s.m {
if !f(v) {
delete(s.m, v)
}
}
}
func TestSet() {
s1 := _Make[int]()
if got := s1.Len(); got != 0 {
panic(fmt.Sprintf("Len of empty set = %d, want 0", got))
}
s1.Add(1)
s1.Add(1)
s1.Add(1)
if got := s1.Len(); got != 1 {
panic(fmt.Sprintf("(%v).Len() == %d, want 1", s1, got))
}
s1.Add(2)
s1.Add(3)
s1.Add(4)
if got := s1.Len(); got != 4 {
panic(fmt.Sprintf("(%v).Len() == %d, want 4", s1, got))
}
if !s1.Contains(1) {
panic(fmt.Sprintf("(%v).Contains(1) == false, want true", s1))
}
if s1.Contains(5) {
panic(fmt.Sprintf("(%v).Contains(5) == true, want false", s1))
}
vals := s1.Values()
sort.Ints(vals)
w1 := []int{1, 2, 3, 4}
if !_SliceEqual(vals, w1) {
panic(fmt.Sprintf("(%v).Values() == %v, want %v", s1, vals, w1))
}
}
func TestEqual() {
s1 := _Make[string]()
s2 := _Make[string]()
if !_Equal(s1, s2) {
panic(fmt.Sprintf("_Equal(%v, %v) = false, want true", s1, s2))
}
s1.Add("hello")
s1.Add("world")
if got := s1.Len(); got != 2 {
panic(fmt.Sprintf("(%v).Len() == %d, want 2", s1, got))
}
if _Equal(s1, s2) {
panic(fmt.Sprintf("_Equal(%v, %v) = true, want false", s1, s2))
}
}
func TestCopy() {
s1 := _Make[float64]()
s1.Add(0)
s2 := s1.Copy()
if !_Equal(s1, s2) {
panic(fmt.Sprintf("_Equal(%v, %v) = false, want true", s1, s2))
}
s1.Add(1)
if _Equal(s1, s2) {
panic(fmt.Sprintf("_Equal(%v, %v) = true, want false", s1, s2))
}
}
func TestAddSet() {
s1 := _Make[int]()
s1.Add(1)
s1.Add(2)
s2 := _Make[int]()
s2.Add(2)
s2.Add(3)
s1.AddSet(s2)
if got := s1.Len(); got != 3 {
panic(fmt.Sprintf("(%v).Len() == %d, want 3", s1, got))
}
s2.Add(1)
if !_Equal(s1, s2) {
panic(fmt.Sprintf("_Equal(%v, %v) = false, want true", s1, s2))
}
}
func TestSubSet() {
s1 := _Make[int]()
s1.Add(1)
s1.Add(2)
s2 := _Make[int]()
s2.Add(2)
s2.Add(3)
s1.SubSet(s2)
if got := s1.Len(); got != 1 {
panic(fmt.Sprintf("(%v).Len() == %d, want 1", s1, got))
}
if vals, want := s1.Values(), []int{1}; !_SliceEqual(vals, want) {
panic(fmt.Sprintf("after SubSet got %v, want %v", vals, want))
}
}
func TestIntersect() {
s1 := _Make[int]()
s1.Add(1)
s1.Add(2)
s2 := _Make[int]()
s2.Add(2)
s2.Add(3)
s1.Intersect(s2)
if got := s1.Len(); got != 1 {
panic(fmt.Sprintf("(%v).Len() == %d, want 1", s1, got))
}
if vals, want := s1.Values(), []int{2}; !_SliceEqual(vals, want) {
panic(fmt.Sprintf("after Intersect got %v, want %v", vals, want))
}
}
func TestIterate() {
s1 := _Make[int]()
s1.Add(1)
s1.Add(2)
s1.Add(3)
s1.Add(4)
tot := 0
s1.Iterate(func(i int) { tot += i })
if tot != 10 {
panic(fmt.Sprintf("total of %v == %d, want 10", s1, tot))
}
}
func TestFilter() {
s1 := _Make[int]()
s1.Add(1)
s1.Add(2)
s1.Add(3)
s1.Filter(func(v int) bool { return v%2 == 0 })
if vals, want := s1.Values(), []int{2}; !_SliceEqual(vals, want) {
panic(fmt.Sprintf("after Filter got %v, want %v", vals, want))
}
}
func main() {
TestSet()
TestEqual()
TestCopy()
TestAddSet()
TestSubSet()
TestIntersect()
TestIterate()
TestFilter()
}