^^

fix mustConvHex docstring

day-1/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-10/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-11/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-12/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-13/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-14/image.go

@@ -25,7 +25,7 @@ func (i img) transposed() []string {
 	return transposed
 }
 
-// String implements the Stringer interface
+// String implements the fmt.Stringer interface
 func (i img) String() string {
 	out := ""
 	for _, line := range i.raw {

day-14/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-15/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-16/debug.go

@@ -0,0 +1,30 @@
+package main
+
+import "fmt"
+
+func printDebug(move *mover, lines []string) int {
+	num := 0
+	for i, line := range lines {
+		for j, r := range line {
+			inNodes := func(c coords) bool {
+				for _, node := range move.nodes {
+					if c.X == node.X && c.Y == node.Y {
+						return true
+					}
+				}
+				return false
+			}(newCoords(j, i))
+
+			if inNodes {
+				fmt.Printf("#")
+				num++
+				//} else if r == '|' || r == '\\' || r == '/' || r == '-' {
+				//fmt.Printf(".")
+			} else {
+				fmt.Printf("%c", r)
+			}
+		}
+		fmt.Println()
+	}
+	return num
+}

day-16/go.mod

@@ -0,0 +1,3 @@
+module github.com/onyx-and-iris/aoc2023/day-16
+
+go 1.21.5

day-16/makefile

@@ -0,0 +1,10 @@
+TEST="test.txt"
+INPUT="input.txt"
+
+test:
+	go run . < $(TEST)
+
+run:
+	go run . < $(INPUT)
+
+all: test

day-16/mover.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"fmt"
+)
+
+type coords struct {
+	X int
+	Y int
+}
+
+func newCoords(x, y int) coords {
+	return coords{X: x, Y: y}
+}
+
+// node represents a single node with coordinates and direction
+type node struct {
+	coords
+	direction int
+}
+
+func newNode(x, y int, direction int) node {
+	return node{coords: newCoords(x, y), direction: direction}
+}
+
+// String implements the fmt.Stringer interface
+func (n node) String() string {
+	return fmt.Sprintf("%v%s", n.coords, dirs[n.direction])
+}
+
+type mover struct {
+	node
+	nodes []node
+}
+
+// newMover sets the start coordinates and direction
+// it returns a mover type
+func newMover(n node) *mover {
+	return &mover{node: n, nodes: make([]node, 0)}
+}
+
+// direction returns the current node direction
+func (m *mover) direction() int {
+	return m.node.direction
+}
+
+// setDirection sets the current node direction
+func (m *mover) setDirection(val int) {
+	m.node.direction = val
+}
+
+// move shifts the X,Y coordinate by one depending on direction
+func (m *mover) move() {
+	switch m.node.direction {
+	case N:
+		m.Y--
+	case S:
+		m.Y++
+	case W:
+		m.X--
+	case E:
+		m.X++
+	}
+}

day-16/one.go

@@ -0,0 +1,125 @@
+package main
+
+import (
+	"math"
+
+	log "github.com/sirupsen/logrus"
+)
+
+const (
+	SPACE    = '.'
+	V_MIRROR = '|'
+	H_MIRROR = '-'
+	F_MIRROR = '/'
+	B_MIRROR = '\\'
+)
+
+const (
+	N = iota
+	S
+	W
+	E
+)
+
+// only for debugging
+var steps int
+var dirs = []string{"N", "S", "W", "E"}
+
+func runner(mover *mover, lines []string) {
+	for steps < math.MaxInt && mover.Y >= 0 && mover.Y < len(lines) && mover.X >= 0 && mover.X < len(lines[mover.Y]) {
+		if nodeInNodes(mover.node, mover.nodes) {
+			log.Debug(mover.node, " in nodes, breaking.")
+			break
+		}
+
+		mover.nodes = append(mover.nodes, mover.node)
+
+		switch lines[mover.Y][mover.X] {
+		case SPACE: // '.'
+			log.Debug("we have space and direction is ", dirs[mover.direction()])
+			mover.move()
+
+		case F_MIRROR: // '/'
+			log.Debug("we have forward mirror and direction is ", dirs[mover.direction()])
+			switch mover.direction() {
+			case N:
+				mover.setDirection(E)
+			case S:
+				mover.setDirection(W)
+			case W:
+				mover.setDirection(S)
+			case E:
+				mover.setDirection(N)
+			}
+			log.Debug("step: ", steps, " ", string(F_MIRROR), " direction changed to ", dirs[mover.direction()])
+			mover.move()
+
+		case B_MIRROR: // '\'
+			log.Debug("we have backwards mirror and direction is ", dirs[mover.direction()])
+			switch mover.direction() {
+			case N:
+				mover.setDirection(W)
+			case S:
+				mover.setDirection(E)
+			case W:
+				mover.setDirection(N)
+			case E:
+				mover.setDirection(S)
+			}
+			log.Debug("step: ", steps, " ", string(B_MIRROR), " direction changed to ", dirs[mover.direction()])
+			mover.move()
+
+		case V_MIRROR: // '|'
+			log.Debug("we have vertical mirror and direction is ", dirs[mover.direction()])
+			if mover.direction() == N || mover.direction() == S {
+				mover.move()
+				continue
+			}
+			if mover.direction() == W || mover.direction() == E {
+				c := mover.coords
+				mover.setDirection(N)
+				mover.move()
+				runner(mover, lines)
+				mover.coords = c
+				mover.setDirection(S)
+				mover.move()
+				runner(mover, lines)
+			}
+
+		case H_MIRROR: // '-'
+			log.Debug("we have horizontal mirror and direction is ", dirs[mover.direction()])
+			if mover.direction() == W || mover.direction() == E {
+				mover.move()
+				continue
+			}
+			if mover.direction() == N || mover.direction() == S {
+				c := mover.coords
+				mover.setDirection(W)
+				mover.move()
+				runner(mover, lines)
+				mover.coords = c
+				mover.setDirection(E)
+				mover.move()
+				runner(mover, lines)
+			}
+
+		default:
+			log.Fatal("unknown node")
+		}
+	}
+	steps++
+}
+
+// one
+func one(lines []string) int {
+	mover := newMover(newNode(0, 0, E))
+
+	runner(mover, lines)
+
+	if log.GetLevel() == log.DebugLevel {
+		n := printDebug(mover, lines)
+		log.Debug("total: ", n)
+	}
+
+	return uniqueNodes(mover)
+}

day-16/solution.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"fmt"
+
+	log "github.com/sirupsen/logrus"
+)
+
+func init() {
+	log.SetLevel(log.InfoLevel)
+}
+
+func main() {
+	lines := readlines()
+
+	ans := one(lines)
+	fmt.Printf("solution one: %d\n", ans)
+
+	ans = two(lines)
+	fmt.Printf("solution two: %d\n", ans)
+}

day-16/two.go

@@ -0,0 +1,77 @@
+package main
+
+import "sync"
+
+// returns the number of unique nodes (reducing multiple nodes with different directions to one)
+func uniqueNodes(mover *mover) int {
+	uniqueCoords := []coords{}
+	for _, node := range mover.nodes {
+		if !coordInCoords(node.coords, uniqueCoords) {
+			uniqueCoords = append(uniqueCoords, node.coords)
+		}
+	}
+	return len(uniqueCoords)
+}
+
+// spawn invoked a single runner with a single mover
+func spawn(i, j, direction int, lines []string) int {
+	m := newMover(newNode(i, j, direction))
+	runner(m, lines)
+	return uniqueNodes(m)
+}
+
+var wg sync.WaitGroup
+
+// two returns the highest energized value for any beam spawn point/direction
+func two(lines []string) int {
+	res := 0
+	n := 0
+
+	for i := 0; i < len(lines[0]); i++ {
+		wg.Add(1)
+		go func(x int) {
+			defer wg.Done()
+
+			n = spawn(x, 0, S, lines)
+			if n > res {
+				res = n
+			}
+		}(i)
+
+		wg.Add(1)
+		go func(x int) {
+			defer wg.Done()
+
+			n = spawn(x, len(lines[0])-1, N, lines)
+			if n > res {
+				res = n
+			}
+		}(i)
+	}
+
+	for i := 0; i < len(lines); i++ {
+		wg.Add(1)
+		go func(y int) {
+			defer wg.Done()
+
+			n = spawn(0, y, E, lines)
+			if n > res {
+				res = n
+			}
+		}(i)
+
+		wg.Add(1)
+		go func(y int) {
+			defer wg.Done()
+
+			n = spawn(len(lines[0])-1, y, W, lines)
+			if n > res {
+				res = n
+			}
+		}(i)
+	}
+
+	wg.Wait()
+
+	return res
+}

day-16/util.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"bufio"
+	"log"
+	"os"
+)
+
+// readlines reads lines from stdin.
+// it returns them as an array of strings
+func readlines() []string {
+	lines := []string{}
+
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+
+	if err := scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+
+	return lines
+}
+
+// nodeInNodes returns true if node n is in nodes
+// X, Y coords and direction must match
+func nodeInNodes(n node, nodes []node) bool {
+	for _, node := range nodes {
+		if n.X == node.X && n.Y == node.Y && n.direction == node.direction {
+			return true
+		}
+	}
+	return false
+}
+
+// coordInCoords returns true if coords c is in coords
+func coordInCoords(c coords, coords []coords) bool {
+	for _, coord := range coords {
+		if c.X == coord.X && c.Y == coord.Y {
+			return true
+		}
+	}
+	return false
+}

day-17/go.mod

@@ -0,0 +1,3 @@
+module github.com/onyx-and-iris/aoc2023/day-17
+
+go 1.21.5

day-17/makefile

@@ -0,0 +1,10 @@
+TEST="test.txt"
+INPUT="input.txt"
+
+test:
+	go run . < $(TEST)
+
+run:
+	go run . < $(INPUT)
+
+all: test

day-17/node.go

@@ -0,0 +1,32 @@
+package main
+
+import "fmt"
+
+type coords struct {
+	X int
+	Y int
+}
+
+func newCoords(x, y int) coords {
+	return coords{X: x, Y: y}
+}
+
+// node represents a single point on the graph
+type node struct {
+	cost       int
+	distance   int
+	directionX int
+	directionY int
+	coords
+	index int
+}
+
+func newNode(cost, distance, directionX, directionY, x, y int) *node {
+	c := newCoords(x, y)
+	return &node{cost: cost, distance: distance, directionX: directionX, directionY: directionY, coords: c}
+}
+
+// String implements the fmt.Stringer interface
+func (n node) String() string {
+	return fmt.Sprintf("%d%d%d%v", n.distance, n.directionX, n.directionY, n.coords)
+}

day-17/one.go

@@ -0,0 +1,114 @@
+package main
+
+import (
+	"container/heap"
+
+	log "github.com/sirupsen/logrus"
+)
+
+type option func(*dijkstra)
+
+func WithMinDistance(distance int) option {
+	return func(d *dijkstra) {
+		d.minDistance = distance
+	}
+}
+
+func WithMaxDistance(distance int) option {
+	return func(d *dijkstra) {
+		d.maxDistance = distance
+	}
+}
+
+type dijkstra struct {
+	graph       [][]int
+	minDistance int
+	maxDistance int
+}
+
+func newDijkstra(graph [][]int, opts ...option) *dijkstra {
+	d := &dijkstra{graph: graph}
+
+	for _, opt := range opts {
+		opt(d)
+	}
+
+	return d
+}
+
+func (d dijkstra) initialize(start coords) *pqueue {
+	pq := newPriorityQueue()
+	heap.Init(pq)
+	// we don't encounter heat loss for start point unless we enter this block again
+	heap.Push(pq, newNode(0, 0, 0, 0, start.X, start.Y))
+	return pq
+}
+
+// run performs the lowest cost dijkstra algorithm from start to end
+func (d dijkstra) run(start, end coords) int {
+	pq := d.initialize(start)
+
+	visited := map[string]bool{}
+
+	for pq.Len() > 0 {
+		cost, node := func() (int, *node) {
+			x := heap.Pop(pq).(*node)
+			return x.cost, x
+		}()
+
+		// we reached final location, return its lowest cost
+		if node.X == end.X && node.Y == end.Y && node.distance >= d.minDistance {
+			log.Debug("returning lowest cost with min distance >= ", d.minDistance)
+			return node.cost
+		}
+
+		if _, ok := visited[node.String()]; ok {
+			continue
+		}
+		visited[node.String()] = true
+
+		var neighbours = [][]int{{0, -1}, {0, 1}, {-1, 0}, {1, 0}} // N, S, W, E
+		for _, n := range neighbours {
+			nextX := node.X + n[0]
+			nextY := node.Y + n[1]
+
+			if nextY < 0 || nextY >= len(d.graph) || nextX < 0 || nextX >= len(d.graph[nextY]) {
+				continue
+			}
+
+			if node.directionX == -n[0] && node.directionY == -n[1] { // are we going backwards?
+				continue
+			}
+
+			var distance = 1
+			if node.directionX == n[0] || node.directionY == n[1] { // same direction
+				distance = node.distance + 1
+			} else {
+				if node.distance < d.minDistance {
+					continue
+				}
+			}
+
+			if distance > d.maxDistance {
+				continue
+			}
+
+			new_cost := cost + d.graph[nextY][nextX]
+			heap.Push(pq, newNode(new_cost, distance, n[0], n[1], nextX, nextY))
+		}
+	}
+
+	return 0
+}
+
+// one returns the lowest cost path for the given graph from start to end coords
+func one(lines []string) int {
+	graph := buildGraph(lines)
+
+	start := newCoords(0, 0)
+	end := newCoords(len(graph[0])-1, len(graph)-1)
+	dijkstra := newDijkstra(graph, WithMaxDistance(3))
+	cost := dijkstra.run(start, end)
+
+	return cost
+}

day-17/pqueue.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"container/heap"
+)
+
+// pqueue represents a min priority queue
+// it implements the heap.Interface interface
+type pqueue []*node
+
+func newPriorityQueue() *pqueue {
+	pq := make(pqueue, 0)
+	return &pq
+}
+
+func (pq pqueue) Len() int {
+	return len(pq)
+}
+
+func (pq *pqueue) Push(x interface{}) {
+	n := len(*pq)
+	node := x.(*node)
+	node.index = n
+	*pq = append(*pq, node)
+}
+
+func (pq *pqueue) Pop() interface{} {
+	old := *pq
+	n := len(old)
+	node := old[n-1]
+	node.index = -1
+	*pq = old[0 : n-1]
+	return node
+}
+
+func (pq *pqueue) Update(node *node, value int) {
+	node.cost = value
+	heap.Fix(pq, node.index)
+}
+
+func (pq pqueue) Less(i, j int) bool {
+	return pq[i].cost < pq[j].cost
+}
+
+func (pq pqueue) Swap(i, j int) {
+	pq[i], pq[j] = pq[j], pq[i]
+	pq[i].index = i
+	pq[j].index = j
+}

day-17/pqueue_test.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"container/heap"
+	"testing"
+
+	"github.com/go-playground/assert/v2"
+)
+
+func TestPriorityQueue(t *testing.T) {
+	//t.Skip("skipping test")
+	pq := newPriorityQueue()
+
+	heap.Push(pq, newNode(30, 0, 0, 0, 0, 0))
+	heap.Push(pq, newNode(10, 0, 0, 0, 8, 0))
+	heap.Push(pq, newNode(20, 0, 0, 0, 13, 0))
+
+	t.Run("Should create a queue size 3", func(t *testing.T) {
+		assert.Equal(t, 3, pq.Len())
+	})
+
+	item := heap.Pop(pq).(*node)
+
+	t.Run("Should return item with cost 10", func(t *testing.T) {
+		assert.Equal(t, 10, item.cost)
+	})
+}

day-17/solution.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"fmt"
+
+	log "github.com/sirupsen/logrus"
+)
+
+func init() {
+	log.SetLevel(log.InfoLevel)
+}
+
+func main() {
+	lines := readlines()
+
+	ans := one(lines)
+	fmt.Printf("solution one: %d\n", ans)
+
+	ans = two(lines)
+	fmt.Printf("solution two: %d\n", ans)
+}

day-17/two.go

@@ -0,0 +1,14 @@
+package main
+
+// two returns the lowest cost path for a given graph from start to end coords
+// with a min/max distance set
+func two(lines []string) int {
+	graph := buildGraph(lines)
+
+	start := newCoords(0, 0)
+	end := newCoords(len(graph[0])-1, len(graph)-1)
+	dijkstra := newDijkstra(graph, WithMinDistance(4), WithMaxDistance(10))
+	cost := dijkstra.run(start, end)
+
+	return cost
+}

day-17/two_test.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	_ "embed"
+	"strings"
+
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var (
+	//go:embed test2.txt
+	testInput2 []byte
+)
+
+func TestDjistraWithMinDistance(t *testing.T) {
+	//t.Skip("skipping test")
+
+	input := strings.Split(string(testInput2), "\n")
+	cost := two(input)
+
+	t.Run("Should return a lowest cost of 71", func(t *testing.T) {
+		assert.Equal(t, 71, cost)
+	})
+}

day-17/util.go

@@ -0,0 +1,38 @@
+package main
+
+import (
+	"bufio"
+	"log"
+	"os"
+)
+
+// readlines reads lines from stdin.
+// it returns them as an array of strings
+func readlines() []string {
+	lines := []string{}
+
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+
+	if err := scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+
+	return lines
+}
+
+// buildGraph parses lines into costs for graph
+func buildGraph(lines []string) [][]int {
+	graph := make([][]int, len(lines))
+
+	for i, line := range lines {
+		graph[i] = make([]int, len(line))
+		for j, r := range line {
+			graph[i][j] = int(r - '0')
+		}
+	}
+
+	return graph
+}

day-18/go.mod

@@ -0,0 +1,3 @@
+module github.com/onyx-and-iris/aoc2023/day-18
+
+go 1.21.5

day-18/imager.go

@@ -0,0 +1,37 @@
+package main
+
+type coords struct {
+	X int
+	Y int
+}
+
+func newCoords(x, y int) coords {
+	return coords{X: x, Y: y}
+}
+
+type imager struct {
+	point coords
+	space []coords
+}
+
+// newImager returns an imager type
+func newImager() *imager {
+	return &imager{point: newCoords(0, 0), space: make([]coords, 0)}
+}
+
+// add appends new coordinates to all points that describe the polygon
+func (i *imager) add(direction string, count int) {
+	for j := 0; j < count; j++ {
+		switch direction {
+		case "U":
+			i.point.Y--
+		case "D":
+			i.point.Y++
+		case "L":
+			i.point.X--
+		case "R":
+			i.point.X++
+		}
+		i.space = append(i.space, newCoords(i.point.X, i.point.Y))
+	}
+}

day-18/makefile

@@ -0,0 +1,10 @@
+TEST="test.txt"
+INPUT="input.txt"
+
+test:
+	go run . < $(TEST)
+
+run:
+	go run . < $(INPUT)
+
+all: test

day-18/one.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"regexp"
+)
+
+var r = regexp.MustCompile(`(?P<direction>[A-Z]) (?P<count>[0-9]+) \((?P<colour>.*)\)`)
+
+func fromRegex(imager *imager, lines []string) {
+	for _, line := range lines {
+		direction, count := func() (string, int) {
+			x := getParams(r, line)
+			return x["direction"], mustConv(x["count"])
+		}()
+		imager.add(direction, count)
+	}
+}
+
+func buildImage(withParser func(imager *imager, lines []string), imager *imager, lines []string) {
+	withParser(imager, lines)
+}
+
+// one returns the area of the polygon described by imager.space
+func one(lines []string) int {
+	imager := newImager()
+	buildImage(fromRegex, imager, lines)
+
+	return calculateArea(imager.space)
+}

day-18/solution.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"fmt"
+
+	log "github.com/sirupsen/logrus"
+)
+
+func init() {
+	log.SetLevel(log.InfoLevel)
+}
+
+func main() {
+	lines := readlines()
+
+	ans := one(lines)
+	fmt.Printf("solution one: %d\n", ans)
+
+	ans = two(lines)
+	fmt.Printf("solution two: %d\n", ans)
+
+}

day-18/two.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"strings"
+)
+
+func fromHex(imager *imager, lines []string) {
+	for _, line := range lines {
+		direction, count := func() (string, int) {
+			var dirs = []string{"R", "D", "L", "U"}
+			m := getParams(r, line)
+			code := strings.TrimLeft(m["colour"], "#")
+			return dirs[mustConv(string(code[len(code)-1]))], mustConvHex(code[:len(code)-1])
+		}()
+		imager.add(direction, count)
+	}
+}
+
+// two returns the area of the polygon described by imager.space
+// it uses the hex codes to define points
+func two(lines []string) int {
+	imager := newImager()
+	buildImage(fromHex, imager, lines)
+
+	return calculateArea(imager.space)
+}

day-18/util.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"bufio"
+	"log"
+	"math"
+	"os"
+	"regexp"
+	"strconv"
+)
+
+// readlines reads lines from stdin.
+// it returns them as an array of strings
+func readlines() []string {
+	lines := []string{}
+
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+
+	if err := scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+
+	return lines
+}
+
+func getParams(rexp *regexp.Regexp, url string) map[string]string {
+	match := rexp.FindStringSubmatch(url)
+
+	m := make(map[string]string)
+	for i, name := range rexp.SubexpNames() {
+		if i > 0 && i <= len(match) {
+			m[name] = match[i]
+		}
+	}
+	return m
+}
+
+// mustConv converts string to int
+// it will panic if an error occurs
+func mustConv(s string) int {
+	n, err := strconv.Atoi(s)
+	if err != nil {
+		panic(err)
+	}
+	return n
+}
+
+// mustConvHex converts a hex string to int
+// it will panic if an error occurs
+func mustConvHex(s string) int {
+	n, err := strconv.ParseInt(s, 16, 64)
+	if err != nil {
+		panic(err)
+	}
+	return int(n)
+}
+
+// calculateArea returns the area of the polygon described by imager.space
+func calculateArea(space []coords) int {
+	area := 0
+	for i := 0; i < len(space); i++ {
+		next := space[(i+1)%len(space)]
+		area += space[i].X*next.Y - space[i].Y*next.X
+	}
+
+	// add perimeter to area within perimeter
+	area = len(space) + (int(math.Abs(float64(area))) / 2)
+
+	return area - len(space)/2 + 1
+}

day-2/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-3/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-4/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-5/data.go

@@ -1,19 +1,22 @@
 package main
 
-type Data struct {
+type data struct {
 	dest   int
 	source int
 	offset int
 }
 
-var seeds = []int{}
+func newData(nums ...int) data {
-
+	return data{dest: nums[0], source: nums[1], offset: nums[2]}
-var dataMap = map[string][]Data{
-	"seed-to-soil":            make([]Data, 0),
-	"soil-to-fertilizer":      make([]Data, 0),
-	"fertilizer-to-water":     make([]Data, 0),
-	"water-to-light":          make([]Data, 0),
-	"light-to-temperature":    make([]Data, 0),
-	"temperature-to-humidity": make([]Data, 0),
-	"humidity-to-location":    make([]Data, 0),
 }
+
+func (d data) transform(start, end int) (int, int) {
+	f := func(x int) int {
+		return x - d.source + d.dest
+	}
+	return f(start), f(end - 1)
+}
+
+var dataMap = map[string][]data{}
+
+var identifiers = []string{}

day-5/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-5/one.go

@@ -2,21 +2,18 @@ package main
 
 import (
 	"math"
-
-	log "github.com/sirupsen/logrus"
 )
 
-var identifiers = []string{"seed-to-soil", "soil-to-fertilizer", "fertilizer-to-water", "water-to-light", "light-to-temperature", "temperature-to-humidity", "humidity-to-location"}
+var seeds = []int{}
 
+// next recursively calculates each destination for each set of data in dataMap
 func next(i int, datapoint int) int {
 	if i == len(identifiers) {
 		return datapoint
 	}
 
-	dest := func() int {
-		datas := dataMap[identifiers[i]]
 	dest := 0
-		for _, data := range datas {
+	for _, data := range dataMap[identifiers[i]] {
 		if datapoint >= data.source && datapoint <= data.source+data.offset {
 			dest = data.dest + (datapoint - data.source)
 			break
@@ -25,20 +22,16 @@ func next(i int, datapoint int) int {
 	if dest == 0 {
 		dest = datapoint
 	}
-		return dest
-	}()
-	//log.Debug(identifiers[i], ": ", dest)
 	return next(i+1, dest)
 }
 
-// one returns the lowest location
+// one returns the lowest location for any seed in seeds
 func one(lines []string) (int, error) {
-	lowest := math.MaxInt
 	parseLines(lines)
 
+	lowest := math.MaxInt
 	for _, seed := range seeds {
 		location := next(0, seed)
-		log.Info(location)
 		if location < lowest {
 			lowest = location
 		}

day-5/queue.go

@@ -0,0 +1,51 @@
+package main
+
+import (
+	log "github.com/sirupsen/logrus"
+)
+
+// queue represents a FIFO queue of bounds
+type queue struct {
+	size     int
+	elements []bound
+}
+
+// newQueue returns a queue type
+// it initializes the queue size and elements
+func newQueue(size int, elems []bound) queue {
+	return queue{size: size, elements: elems}
+}
+
+// enqueue adds an item to the queue
+func (q *queue) enqueue(elem bound) {
+	if q.size >= 0 && q.getLength() == q.size {
+		log.Info("Queue Overflow")
+		return
+	}
+	q.elements = append(q.elements, elem)
+}
+
+// dequeue pops an element from the start of the queue
+func (q *queue) dequeue() bound {
+	if q.isEmpty() {
+		log.Info("Queue UnderFlow")
+		return bound{}
+	}
+	element := q.elements[0]
+	if q.getLength() == 1 {
+		q.elements = nil
+		return element
+	}
+	q.elements = q.elements[1:]
+	return element
+}
+
+// getLength returns the number of items in the queue
+func (q *queue) getLength() int {
+	return len(q.elements)
+}
+
+// isEmpty returns true if no items are in the queue
+func (q *queue) isEmpty() bool {
+	return len(q.elements) == 0
+}

day-5/solution.go

@@ -7,7 +7,7 @@ import (
 )
 
 func init() {
-	log.SetLevel(log.DebugLevel)
+	log.SetLevel(log.InfoLevel)
 }
 
 func main() {
@@ -19,9 +19,6 @@ func main() {
 	}
 	fmt.Printf("solution one: %d\n", ans)
 
-	ans, err = two(lines)
+	ans = two(lines)
-	if err != nil {
-		log.Fatal(err)
-	}
 	fmt.Printf("solution two: %d\n", ans)
 }

day-5/two.go

@@ -1,78 +1,89 @@
 package main
 
 import (
-	"fmt"
 	"math"
 	"sync"
-	"sync/atomic"
-	"time"
-
-	log "github.com/sirupsen/logrus"
 )
 
-type WaitGroupCount struct {
+var wg sync.WaitGroup
-	sync.WaitGroup
+var mu sync.Mutex
-	count int64
-}
 
-func (wg *WaitGroupCount) Add(delta int) {
+const UNLIMITED = -1
-	atomic.AddInt64(&wg.count, int64(delta))
-	wg.WaitGroup.Add(delta)
-}
-
-func (wg *WaitGroupCount) Done() {
-	atomic.AddInt64(&wg.count, -1)
-	wg.WaitGroup.Done()
-}
-
-func (wg *WaitGroupCount) GetCount() int {
-	return int(atomic.LoadInt64(&wg.count))
-}
-
-var wg = WaitGroupCount{}
-
-//var checked = make([]bound, 0)
 
+// bound represents the lower and upper limits of a single range
 type bound struct {
-	start int
+	lower, upper int
-	end   int
 }
 
-var bounds = []bound{}
+// newBound returns a bound type
-
+// it defines an open ended interval
-// two returns the lowest location
+func newBound(lower, upper int) bound {
-func two(lines []string) (int, error) {
+	return bound{lower: lower, upper: upper - 1}
-	lowest := math.MaxInt
-
-	for i := 0; i < len(seeds); i += 2 {
-		bounds = append(bounds, bound{start: seeds[i], end: seeds[i] + seeds[i+1]})
 }
 
-	startTime := time.Now()
+// nextTransform recursively calculates each new set of seed ranges for each set of data in dataMap
-
+func nextTransform(i int, in []bound) []bound {
-	go func() {
+	if i == len(identifiers) {
-		for {
+		return in
-			elapsed := time.Since(startTime)
-			fmt.Printf("[%s] wg count: %d\n", elapsed.Round(time.Second), wg.GetCount())
-			time.Sleep(time.Second)
 	}
+
+	q := newQueue(UNLIMITED, in)
+	in = make([]bound, 0)
+	for !q.isEmpty() {
+		r := q.dequeue()
+
+		hasOverlap := func() bool {
+			for _, data := range dataMap[identifiers[i]] {
+				start := max(r.lower, data.source)
+				end := min(r.upper, data.source+data.offset)
+
+				if isOverlapping(start, end) {
+					// add new seed range
+					in = append(in, newBound(data.transform(start, end)))
+
+					// append unmatched portions of seed range back into queue
+					if start > r.lower {
+						q.enqueue(newBound(r.lower, start))
+					}
+					if r.upper > end {
+						q.enqueue(newBound(end, r.upper))
+					}
+					return true
+				}
+			}
+			return false
 		}()
 
-	for _, bound := range bounds {
+		// there was no overlap, add the seed range as is
+		if !hasOverlap {
+			in = append(in, r)
+		}
+	}
+
+	return nextTransform(i+1, in)
+}
+
+// two returns the lowest location for any seed in seedRanges
+func two(lines []string) int {
+	var seedRanges = []bound{}
+	for i := 0; i < len(seeds); i += 2 {
 		wg.Add(1)
-		go func(start int, end int) {
+		go func(i int) {
 			defer wg.Done()
-			for i := start; i < end; i++ {
+			mu.Lock()
-				location := next(0, i)
+			seedRanges = append(seedRanges, nextTransform(0, []bound{newBound(seeds[i], seeds[i]+seeds[i+1])})...)
-				if location < lowest {
+			mu.Unlock()
-					lowest = location
+		}(i)
-				}
-			}
-		}(bound.start, bound.end)
-		log.Info(bound, " completed")
 	}
 
 	wg.Wait()
 
-	return lowest - 1, nil // returning a value one too high? not sure why.
+	lowest := math.MaxInt
+	for _, r := range seedRanges {
+		if r.lower < lowest {
+			lowest = r.lower
+		}
+	}
+
+	return lowest
 }

day-5/util.go

@@ -2,12 +2,13 @@ package main
 
 import (
 	"bufio"
-	"log"
 	"os"
 	"regexp"
 	"strconv"
 	"strings"
 	"unicode"
+
+	log "github.com/sirupsen/logrus"
 )
 
 // readlines reads lines from stdin.
@@ -27,28 +28,27 @@ func readlines() []string {
 	return lines
 }
 
+var r = regexp.MustCompile(`([\w-]+) map[:]`)
+
 // parseLines parses input to a data map
 func parseLines(lines []string) {
-	var _regex_identifier = regexp.MustCompile(`(?P<identifier>[\w-]+) map[:]`)
-
 	f := func(c rune) bool {
 		return !unicode.IsDigit(c)
 	}
 
-	for i := 0; i < len(lines); i++ {
+	seeds = convertToInts(strings.FieldsFunc(lines[0], f))
-		if i == 0 {
-			seeds = convertToInts(strings.FieldsFunc(lines[i], f))
-			continue
-		}
 
-		m := _regex_identifier.FindStringSubmatch(lines[i])
+	for i := 2; i < len(lines); i++ {
+		m := r.FindStringSubmatch(lines[i])
 		if len(m) == 2 {
+			identifiers = append(identifiers, m[1])
 			for i = i + 1; i < len(lines) && len(lines[i]) != 0; i++ {
-				nums := convertToInts(strings.FieldsFunc(lines[i], f))
+				d := newData(convertToInts(strings.FieldsFunc(lines[i], f))...)
-				dataMap[m[1]] = append(dataMap[m[1]], Data{dest: nums[0], source: nums[1], offset: nums[2]})
+				dataMap[m[1]] = append(dataMap[m[1]], d)
 			}
 		}
 	}
+	log.Debug(identifiers)
 }
 
 // convertToInts converts a string representing ints to an array of ints
@@ -61,13 +61,8 @@ func convertToInts(data []string) []int {
 	return nums
 }
 
-/*
+// isOverlapping returns true if two ranges overlap. see:
-func isChecked(i int) bool {
+// https://stackoverflow.com/questions/325933/determine-whether-two-date-ranges-overlap/325964#325964
-	for _, bound := range checked {
+func isOverlapping(maxStart, minEnd int) bool {
-		if i > bound.start && i < bound.end {
+	return maxStart < minEnd
-			return true
 }
-	}
-	return false
-}
-*/

day-6/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-7/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-8/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test

day-9/makefile

@@ -2,9 +2,9 @@ TEST="test.txt"
 INPUT="input.txt"
 
 test:
-	cat $(TEST) | go run .
+	go run . < $(TEST)
 
 run:
-	cat $(INPUT) | go run .
+	go run . < $(INPUT)
 
 all: test