mirror of
https://github.com/tailscale/tailscale.git
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217 lines
3.5 KiB
Go
217 lines
3.5 KiB
Go
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package heap
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import (
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"math/rand"
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"testing"
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"golang.org/x/exp/constraints"
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)
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type myHeap[T constraints.Ordered] []T
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func (h *myHeap[T]) Less(i, j int) bool {
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return (*h)[i] < (*h)[j]
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}
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func (h *myHeap[T]) Swap(i, j int) {
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(*h)[i], (*h)[j] = (*h)[j], (*h)[i]
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}
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func (h *myHeap[T]) Len() int {
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return len(*h)
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}
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func (h *myHeap[T]) Pop() (v T) {
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*h, v = (*h)[:h.Len()-1], (*h)[h.Len()-1]
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return
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}
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func (h *myHeap[T]) Push(v T) {
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*h = append(*h, v)
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}
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func (h myHeap[T]) verify(t *testing.T, i int) {
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t.Helper()
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n := h.Len()
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j1 := 2*i + 1
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j2 := 2*i + 2
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if j1 < n {
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if h.Less(j1, i) {
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t.Errorf("heap invariant invalidated [%d] = %v > [%d] = %v", i, h[i], j1, h[j1])
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return
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}
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h.verify(t, j1)
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}
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if j2 < n {
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if h.Less(j2, i) {
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t.Errorf("heap invariant invalidated [%d] = %v > [%d] = %v", i, h[i], j1, h[j2])
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return
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}
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h.verify(t, j2)
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}
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}
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func TestInit0(t *testing.T) {
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h := new(myHeap[int])
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for i := 20; i > 0; i-- {
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h.Push(0) // all elements are the same
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}
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Init[int](h)
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h.verify(t, 0)
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for i := 1; h.Len() > 0; i++ {
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x := Pop[int](h)
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h.verify(t, 0)
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if x != 0 {
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t.Errorf("%d.th pop got %d; want %d", i, x, 0)
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}
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}
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}
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func TestInit1(t *testing.T) {
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h := new(myHeap[int])
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for i := 20; i > 0; i-- {
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h.Push(i) // all elements are different
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}
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Init[int](h)
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h.verify(t, 0)
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for i := 1; h.Len() > 0; i++ {
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x := Pop[int](h)
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h.verify(t, 0)
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if x != i {
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t.Errorf("%d.th pop got %d; want %d", i, x, i)
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}
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}
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}
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func Test(t *testing.T) {
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h := new(myHeap[int])
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h.verify(t, 0)
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for i := 20; i > 10; i-- {
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h.Push(i)
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}
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Init[int](h)
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h.verify(t, 0)
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for i := 10; i > 0; i-- {
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Push[int](h, i)
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h.verify(t, 0)
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}
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for i := 1; h.Len() > 0; i++ {
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x := Pop[int](h)
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if i < 20 {
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Push[int](h, 20+i)
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}
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h.verify(t, 0)
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if x != i {
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t.Errorf("%d.th pop got %d; want %d", i, x, i)
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}
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}
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}
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func TestRemove0(t *testing.T) {
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h := new(myHeap[int])
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for i := 0; i < 10; i++ {
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h.Push(i)
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}
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h.verify(t, 0)
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for h.Len() > 0 {
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i := h.Len() - 1
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x := Remove[int](h, i)
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if x != i {
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t.Errorf("Remove(%d) got %d; want %d", i, x, i)
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}
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h.verify(t, 0)
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}
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}
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func TestRemove1(t *testing.T) {
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h := new(myHeap[int])
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for i := 0; i < 10; i++ {
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h.Push(i)
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}
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h.verify(t, 0)
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for i := 0; h.Len() > 0; i++ {
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x := Remove[int](h, 0)
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if x != i {
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t.Errorf("Remove(0) got %d; want %d", x, i)
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}
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h.verify(t, 0)
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}
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}
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func TestRemove2(t *testing.T) {
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N := 10
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h := new(myHeap[int])
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for i := 0; i < N; i++ {
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h.Push(i)
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}
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h.verify(t, 0)
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m := make(map[int]bool)
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for h.Len() > 0 {
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m[Remove[int](h, (h.Len()-1)/2)] = true
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h.verify(t, 0)
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}
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if len(m) != N {
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t.Errorf("len(m) = %d; want %d", len(m), N)
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}
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for i := 0; i < len(m); i++ {
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if !m[i] {
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t.Errorf("m[%d] doesn't exist", i)
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}
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}
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}
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func BenchmarkDup(b *testing.B) {
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const n = 10000
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h := make(myHeap[int], 0, n)
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for i := 0; i < b.N; i++ {
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for j := 0; j < n; j++ {
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Push[int](&h, 0) // all elements are the same
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}
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for h.Len() > 0 {
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Pop[int](&h)
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}
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}
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}
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func TestFix(t *testing.T) {
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h := new(myHeap[int])
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h.verify(t, 0)
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for i := 200; i > 0; i -= 10 {
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Push[int](h, i)
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}
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h.verify(t, 0)
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if (*h)[0] != 10 {
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t.Fatalf("Expected head to be 10, was %d", (*h)[0])
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}
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(*h)[0] = 210
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Fix[int](h, 0)
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h.verify(t, 0)
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for i := 100; i > 0; i-- {
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elem := rand.Intn(h.Len())
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if i&1 == 0 {
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(*h)[elem] *= 2
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} else {
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(*h)[elem] /= 2
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}
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Fix[int](h, elem)
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h.verify(t, 0)
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}
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}
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