fix day-5 p2

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{}
-
-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 newData(nums ...int) data {
+	return data{dest: nums[0], source: nums[1], offset: nums[2]}
 }
+
+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/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)
-	if err != nil {
-		log.Fatal(err)
-	}
+	ans = two(lines)
 	fmt.Printf("solution two: %d\n", ans)
 }

day-5/two.go

@@ -1,78 +1,85 @@
 package main
 
 import (
-	"fmt"
 	"math"
 	"sync"
-	"sync/atomic"
-	"time"
-
-	log "github.com/sirupsen/logrus"
 )
 
-type WaitGroupCount struct {
-	sync.WaitGroup
-	count int64
-}
+var wg sync.WaitGroup
 
-func (wg *WaitGroupCount) Add(delta int) {
-	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)
+const UNLIMITED = -1
 
+// bound represents the lower and upper limits of a single range
 type bound struct {
-	start int
-	end   int
+	lower, upper int
 }
 
-var bounds = []bound{}
+// newBound returns a bound type
+func newBound(lower, upper int) bound {
+	return bound{lower: lower, upper: upper}
+}
 
-// two returns the lowest location
-func two(lines []string) (int, error) {
-	lowest := math.MaxInt
-
-	for i := 0; i < len(seeds); i += 2 {
-		bounds = append(bounds, bound{start: seeds[i], end: seeds[i] + seeds[i+1]})
+// nextTransform recursively calculates each new set of seed ranges for each set of data in dataMap
+func nextTransform(i int, in []bound) []bound {
+	if i == len(identifiers) {
+		return in
 	}
 
-	startTime := time.Now()
+	q := newQueue(UNLIMITED, in)
+	in = make([]bound, 0)
+	for !q.isEmpty() {
+		r := q.dequeue()
 
-	go func() {
-		for {
-			elapsed := time.Since(startTime)
-			fmt.Printf("[%s] wg count: %d\n", elapsed.Round(time.Second), wg.GetCount())
-			time.Sleep(time.Second)
+		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-1))
 					}
+					if r.upper > end {
+						q.enqueue(newBound(end, r.upper-1))
+					}
+					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++ {
-				location := next(0, i)
-				if location < lowest {
-					lowest = location
-				}
-			}
-		}(bound.start, bound.end)
-		log.Info(bound, " completed")
+			seedRanges = append(seedRanges, nextTransform(0, []bound{newBound(seeds[i], seeds[i]+seeds[i+1]-1)})...)
+		}(i)
 	}
 
 	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++ {
-		if i == 0 {
-			seeds = convertToInts(strings.FieldsFunc(lines[i], f))
-			continue
-		}
+	seeds = convertToInts(strings.FieldsFunc(lines[0], f))
 
-		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))
-				dataMap[m[1]] = append(dataMap[m[1]], Data{dest: nums[0], source: nums[1], offset: nums[2]})
+				d := newData(convertToInts(strings.FieldsFunc(lines[i], f))...)
+				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
 }
 
-/*
-func isChecked(i int) bool {
-	for _, bound := range checked {
-		if i > bound.start && i < bound.end {
-			return true
-		}
-	}
-	return false
+// isOverlapping returns true if two ranges overlap. see:
+// https://stackoverflow.com/questions/325933/determine-whether-two-date-ranges-overlap/325964#325964
+func isOverlapping(maxStart, minEnd int) bool {
+	return maxStart < minEnd
 }
-*/