chore(aos): add compress graph

aoc_test.go

@@ -9,66 +9,6 @@ import (
 	aoc "go.sour.is/advent-of-code"
 )
 
-func TestReverse(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(aoc.Reverse([]int{1, 2, 3, 4}), []int{4, 3, 2, 1})
-}
-
-func TestLCM(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(aoc.LCM([]int{}...), 0)
-	is.Equal(aoc.LCM(5), 5)
-	is.Equal(aoc.LCM(5, 3), 15)
-	is.Equal(aoc.LCM(5, 3, 2), 30)
-}
-
-func TestReadStringToInts(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(aoc.ReadStringToInts([]string{"1", "2", "3"}), []int{1, 2, 3})
-}
-
-func TestRepeat(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(aoc.Repeat(5, 3), []int{5, 5, 5})
-}
-
-func TestPower2(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(aoc.Power2(0), 1)
-	is.Equal(aoc.Power2(1), 2)
-	is.Equal(aoc.Power2(2), 4)
-}
-
-func TestABS(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(aoc.ABS(1), 1)
-	is.Equal(aoc.ABS(0), 0)
-	is.Equal(aoc.ABS(-1), 1)
-}
-
-func TestTranspose(t *testing.T) {
-	is := is.New(t)
-
-	is.Equal(
-		aoc.Transpose(
-			[][]int{
-				{1, 1},
-				{0, 0},
-				{1, 1},
-			},
-		),
-		[][]int{
-			{1, 0, 1},
-			{1, 0, 1},
-		},
-	)
-}
 
 func TestList(t *testing.T) {
 	is := is.New(t)
@@ -116,23 +56,6 @@ func TestPriorityQueue(t *testing.T) {
 	is.True(v == nil)
 }
 
-func TestSet(t *testing.T) {
-	is := is.New(t)
-
-	s := aoc.Set(1, 2, 3)
-	is.True(!s.Has(0))
-	is.True(s.Has(1))
-	is.True(s.Has(2))
-	is.True(s.Has(3))
-	is.True(!s.Has(4))
-
-	s.Add(4)
-	is.True(s.Has(4))
-
-	items := s.Items()
-	sort.Ints(items)
-	is.Equal(items, []int{1, 2, 3, 4})
-}
 
 func ExamplePriorityQueue() {
 	type memo struct {
@@ -194,26 +117,6 @@ func ExamplePriorityQueue() {
 	// point 5 is 22 steps away.
 	// point 6 is 19 steps away.
 }
-
-func TestStack(t *testing.T) {
-	is := is.New(t)
-
-	s := aoc.Stack(1, 2, 3, 4)
-	is.True(!s.IsEmpty())
-	is.Equal(s.Pop(), 4)
-	is.Equal(s.Pop(), 3)
-	is.Equal(s.Pop(), 2)
-	is.Equal(s.Pop(), 1)
-	is.True(s.IsEmpty())
-	s.Push(4, 3, 2, 1)
-	is.True(!s.IsEmpty())
-	is.Equal(s.Pop(), 1)
-	is.Equal(s.Pop(), 2)
-	is.Equal(s.Pop(), 3)
-	is.Equal(s.Pop(), 4)
-	is.True(s.IsEmpty())
-}
-
 func TestGraph(t *testing.T) {
 	is := is.New(t)
 

grids.go

@@ -3,6 +3,8 @@ package aoc
 import (
 	"cmp"
 	"sort"
+
+	"golang.org/x/exp/maps"
 )
 
 type Vector struct {
@@ -82,6 +84,76 @@ func (m *Map[I, T]) Valid(p Point[I]) bool {
 	return p[0] >= 0 && p[0] < rows && p[1] >= 0 && p[1] < cols
 }
 
+type cmap[C number, N comparable] struct {
+	base      pather[C, N]
+	neighbors map[N]map[N]C
+}
+
+func (m *cmap[C, N]) Cost(a, b N) C {
+	if v, ok := m.neighbors[a]; ok {
+		return v[b]
+	}
+	return 0
+}
+func (m *cmap[C, N]) Neighbors(n N) []N {
+	if v, ok := m.neighbors[n]; ok {
+		return maps.Keys(v)
+	}
+	return nil
+}
+func (m *cmap[C, N]) Target(n N, c C) bool {
+	return m.base.Target(n, c)
+}
+func (m *cmap[C, N]) String() string {
+	var b = &strings.Builder{}
+
+	for k, nbs := range m.neighbors {
+		fmt.Fprintln(b, k)
+		for to, v := range nbs {
+			fmt.Fprintln(b, "  ", to, k)
+		}
+	}
+
+	return b.String()
+}
+
+func CompressMap[C number, N comparable](p pather[C, N], start N) pather[C, N] {
+	var next = []N{start}
+	var visited = make(map[N]map[N]C)
+
+	var n N
+	for len(next) > 0 {
+		n, next = next[len(next)-1], next[:len(next)-1]
+
+		if _, ok := visited[n]; ok {
+			continue
+		}
+
+		nbs := p.Neighbors(n)
+		if len(nbs) == 2 {
+			a, b := nbs[0], nbs[1]
+			if to, ok := visited[a]; ok {
+				to[b] = to[n] + p.Cost(n, b)
+				delete(to, n)
+				visited[a] = to
+			} else  if to, ok := visited[b]; ok {
+				to[a] = to[n] + p.Cost(n, a)
+				delete(to, n)
+				visited[b] = to
+			}
+			continue
+		}
+
+		visited[n] = make(map[N]C)
+		next = append(next, nbs...)
+		for _, to := range nbs {
+			visited[n][to] = p.Cost(n, to)
+		}
+	}
+
+	return &cmap[C, N]{base: p, neighbors: visited}
+}
+
 type adjacencyList[V any, C comparable] map[C][]V
 type graph[V any, W cmp.Ordered, C comparable] map[C]*vertex[V, W]
 type graphOption[V any, W cmp.Ordered, C comparable] func(g *graph[V, W, C])
@@ -170,5 +242,3 @@ func WithAdjacencyList[W cmp.Ordered, C comparable](list adjacencyList[C, C]) gr
 		}
 	}
 }
-
-// func GraphFromMap()

itertools_test.go

@@ -0,0 +1,47 @@
+package aoc_test
+
+import (
+	"fmt"
+	"sort"
+	"testing"
+
+	"github.com/matryer/is"
+	aoc "go.sour.is/advent-of-code"
+)
+
+func TestReverse(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(aoc.Reverse([]int{1, 2, 3, 4}), []int{4, 3, 2, 1})
+}
+
+func TestReadStringToInts(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(aoc.ReadStringToInts([]string{"1", "2", "3"}), []int{1, 2, 3})
+}
+
+func TestRepeat(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(aoc.Repeat(5, 3), []int{5, 5, 5})
+}
+
+
+func TestTranspose(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(
+		aoc.Transpose(
+			[][]int{
+				{1, 1},
+				{0, 0},
+				{1, 1},
+			},
+		),
+		[][]int{
+			{1, 0, 1},
+			{1, 0, 1},
+		},
+	)
+}

math_test.go

@@ -0,0 +1,27 @@
+package aoc_test
+
+
+func TestLCM(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(aoc.LCM([]int{}...), 0)
+	is.Equal(aoc.LCM(5), 5)
+	is.Equal(aoc.LCM(5, 3), 15)
+	is.Equal(aoc.LCM(5, 3, 2), 30)
+}
+
+func TestPower2(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(aoc.Power2(0), 1)
+	is.Equal(aoc.Power2(1), 2)
+	is.Equal(aoc.Power2(2), 4)
+}
+
+func TestABS(t *testing.T) {
+	is := is.New(t)
+
+	is.Equal(aoc.ABS(1), 1)
+	is.Equal(aoc.ABS(0), 0)
+	is.Equal(aoc.ABS(-1), 1)
+}

search.go

@@ -42,30 +42,6 @@ func (pq *priorityQueue[T]) ExtractMin() *T {
 	return elem
 }
 
-type stack[T any] []T
-
-func Stack[T any](a ...T) *stack[T] {
-	var s stack[T] = a
-	return &s
-}
-func (s *stack[T]) Push(a ...T) {
-	if s == nil {
-		return
-	}
-	*s = append(*s, a...)
-}
-func (s *stack[T]) IsEmpty() bool {
-	return s == nil || len(*s) == 0
-}
-func (s *stack[T]) Pop() T {
-	var a T
-	if s.IsEmpty() {
-		return a
-	}
-	a, *s = (*s)[len(*s)-1], (*s)[:len(*s)-1]
-	return a
-}
-
 // ManhattanDistance the distance between two points measured along axes at right angles.
 func ManhattanDistance[T integer](a, b Point[T]) T {
 	return ABS(a[0]-b[0]) + ABS(a[1]-b[1])

set_test.go

@@ -0,0 +1,20 @@
+package aoc_test
+
+
+func TestSet(t *testing.T) {
+	is := is.New(t)
+
+	s := aoc.Set(1, 2, 3)
+	is.True(!s.Has(0))
+	is.True(s.Has(1))
+	is.True(s.Has(2))
+	is.True(s.Has(3))
+	is.True(!s.Has(4))
+
+	s.Add(4)
+	is.True(s.Has(4))
+
+	items := s.Items()
+	sort.Ints(items)
+	is.Equal(items, []int{1, 2, 3, 4})
+}