diff --git a/2018/day15/day15-overthink b/2018/day15/day15-overthink
new file mode 100644
index 0000000..84a794c
--- /dev/null
+++ b/2018/day15/day15-overthink
@@ -0,0 +1,203 @@
+package overthink
+
+import (
+	"bufio"
+	"fmt"
+	"math"
+	"os"
+	"sort"
+	"time"
+)
+
+const (
+	UseEmoji    = false
+	MaxInt      = int(^uint(0) >> 1)
+	ClearScreen = "\033[H\033[2J"
+
+	DIR_N = -1i
+	DIR_E = 1
+	DIR_S = 1i
+	DIR_W = -1
+)
+
+var width int
+var input []byte
+
+var elves []*complex64
+var goblins []*complex64
+var allChars []*complex64
+var charMap map[complex64]*Character
+
+func main() {
+	stdinToByteSlice()
+	setupBattle()
+	part1()
+}
+
+func part1() {
+	//for {
+	sortCharacters()
+	printBattleField()
+	for _, c := range allChars {
+		charMap[*c].tick()
+	}
+	time.Sleep(time.Millisecond * 250)
+	printBattleField()
+	//}
+	fmt.Println("")
+}
+
+func sortCharacters() {
+	sort.Sort(ByPos(allChars))
+	sort.Sort(ByPos(elves))
+	sort.Sort(ByPos(goblins))
+}
+
+type Character struct {
+	tp     byte
+	pos    complex64
+	power  int
+	health int
+}
+
+func (c *Character) tick() {
+	// If we're already in range of a target, don't look for a new one
+	var alreadyAtTarget bool
+	var chosenTarget *complex64
+	lowestTargetHp := MaxInt
+	for _, v := range elves {
+		if c.isAdjacentTo(*v) {
+			if charMap[*v].health < lowestTargetHp {
+				chosenTarget = v
+			}
+			alreadyAtTarget = true
+		}
+	}
+	if alreadyAtTarget {
+		// Attack the target
+		charMap[*chosenTarget].health -= c.power
+	} else {
+		// Looking for a target
+		if c.tp == 'G' {
+			// First identify all possible targets (elves that have an open adjacent space)
+			for _, v := range elves {
+
+			}
+		} else {
+			// First identify all possible targets (goblins that have an open adjacent space)
+			for _, v := range goblins {
+			}
+		}
+	}
+}
+
+func (c *Character) isAdjacentTo(p complex64) bool {
+	return c.pos+DIR_N == p || c.pos+DIR_E == p ||
+		c.pos+DIR_S == p || c.pos+DIR_W == p
+}
+
+func (c *Character) hasOpenFlank() bool {
+
+}
+
+// Not sure if we'll use this...
+func manhattanDistance(p1, p2 complex64) int {
+	x1, y1, x2, y2 := real(p1), imag(p1), real(p2), imag(p2)
+	return int(math.Abs(float64(x1)-float64(x2)) + math.Abs(float64(y1)-float64(y2)))
+}
+
+// We have to sort the characters on each tick by y,x position
+// y is the imaginary part, x is the real part
+type ByPos []*complex64
+
+func (c ByPos) Len() int      { return len(c) }
+func (c ByPos) Swap(i, j int) { c[i], c[j] = c[j], c[i] }
+func (c ByPos) Less(i, j int) bool {
+	return imag(*c[i]) < imag(*c[j]) ||
+		(imag(*c[i]) == imag(*c[j]) && real(*c[i]) < real(*c[j]))
+}
+
+// getByte pulls a byte from the given position in the input
+func getByte(pos complex64) byte {
+	return input[int(real(pos))+int(imag(pos))*width]
+}
+
+func setByte(pos complex64, b byte) {
+	input[int(real(pos))+int(imag(pos))*width] = b
+}
+
+func getPosFromInt(i int) complex64 {
+  return complex(float32(i%width), float32(i/width))
+}
+
+func printBattleField() {
+	fmt.Print(ClearScreen)
+	for i := 0; i < len(input); i++ {
+		pos := getPosFromInt(i)
+		var bt byte
+		if c, ok := charMap[pos]; ok {
+			if UseEmoji {
+				switch c.tp {
+				case 'G':
+					if UseEmoji {
+						fmt.Print("👺")
+					}
+				case 'E':
+					fmt.Print("😃")
+				}
+			} else {
+				fmt.Print(string(c.tp))
+			}
+			bt = c.tp
+		} else {
+			bt = getByte(pos)
+			if UseEmoji {
+				if bt == '#' {
+					fmt.Print("🏿")
+				} else {
+					fmt.Print("  ")
+				}
+			} else {
+				fmt.Print(string(bt))
+			}
+		}
+		if i%width == width-1 {
+			fmt.Println("")
+		}
+	}
+}
+
+func setupBattle() {
+	charMap = make(map[complex64]*Character)
+	for i := 0; i < len(input); i++ {
+		pos := complex(float32(i%width), float32(i/width))
+		bt := getByte(pos)
+		if bt == 'G' || bt == 'E' {
+			charMap[pos] = &Character{
+				tp:     bt,
+				pos:    pos,
+				power:  3,
+				health: 200,
+			}
+			setByte(pos, '.')
+			allChars = append(allChars, &charMap[pos].pos)
+			switch bt {
+			case 'G':
+				goblins = append(goblins, &charMap[pos].pos)
+			case 'E':
+				elves = append(elves, &charMap[pos].pos)
+			}
+		}
+	}
+}
+
+func stdinToByteSlice() {
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		data := scanner.Bytes()
+		if width == 0 {
+			width = len(data)
+		}
+		input = append(input, data...)
+	}
+}
diff --git a/2018/day15/day15.go b/2018/day15/day15.go
new file mode 100644
index 0000000..d7aae8d
--- /dev/null
+++ b/2018/day15/day15.go
@@ -0,0 +1,413 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"math"
+	"os"
+	"sort"
+	"time"
+)
+
+/*
+ * 173327 is too low
+ */
+var input []byte
+var width int
+var characters map[complex64]*Character
+var charSlice []*complex64
+var turnCount int
+
+const (
+	ClearScreen = "\033[H\033[2J"
+	MaxInt      = int(^uint(0) >> 1)
+
+	DIR_N = -1i
+	DIR_E = 1
+	DIR_S = 1i
+	DIR_W = -1
+)
+
+func main() {
+	characters = make(map[complex64]*Character)
+	stdinToByteSlice()
+	setupBattle()
+	part1()
+}
+
+func part1() {
+	for {
+		charSlice = charSlice[0:0]
+		for i := 0; i < len(input); i++ {
+			pos := getPosFromInt(i)
+			bt := getByte(pos)
+			if bt == 'G' || bt == 'E' {
+				charSlice = append(charSlice, &pos)
+			}
+		}
+		sort.Sort(ByPos(charSlice))
+		fmt.Printf("= Turn %d =\n", turnCount)
+		printBattlefield()
+		for _, v := range charSlice {
+			if char, ok := characters[*v]; ok {
+				if !char.tick() {
+					break
+				}
+			}
+		}
+
+		if false {
+			time.Sleep(time.Millisecond * 250)
+		}
+		printBattlefield()
+		if checkBattleOver() {
+			break
+		}
+		turnCount++
+	}
+	var totalHP int
+	sort.Sort(ByPos(charSlice))
+	for _, v := range charSlice {
+		if c, ok := characters[*v]; ok {
+			fmt.Println(c.string())
+			totalHP += c.health
+		}
+	}
+	fmt.Println(turnCount, totalHP)
+	fmt.Println("Result:", (totalHP * turnCount))
+}
+
+func checkBattleOver() bool {
+	var elves, gobs int
+	for _, v := range characters {
+		if v.tp == 'E' {
+			elves++
+		} else if v.tp == 'G' {
+			gobs++
+		}
+	}
+	return elves == 0 || gobs == 0
+}
+
+type Character struct {
+	tp     byte
+	health int
+	power  int
+	pos    complex64
+	kills  int
+}
+
+func (c *Character) hasEnemies() bool {
+	for _, oppPos := range charSlice {
+		if v, ok := characters[*oppPos]; ok {
+			if v.tp != c.tp {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+func (c *Character) tick() bool {
+	// If we're already in range of a target, don't look for a new one
+	if tPos, err := c.easiestAdjacentTarget(); err == nil {
+		c.attack(tPos)
+		return c.hasEnemies()
+	}
+	// If we have no open sides, we can't more
+	if !c.hasOpenFlank() {
+		fmt.Println(c.string(), "blocked in")
+		return true
+	}
+	// Otherwise, find a target
+	var opportunities []complex64
+	for _, oppPos := range charSlice {
+		if v, ok := characters[*oppPos]; ok {
+			if v.tp != c.tp {
+				opportunities = append(opportunities, *oppPos)
+			}
+		}
+	}
+	/*
+		var opportunities []complex64
+		for _, oppPos := range charSlice {
+			if v, ok := characters[*oppPos]; ok {
+				if v.tp != c.tp {
+					fmt.Println(c.string(), "checking:", v.string())
+					opportunities = append(opportunities, v.getOpenSides()...)
+				}
+			}
+		}
+		closestDistance := MaxInt
+		var closestPos complex64
+		for _, v := range opportunities {
+			if distance(c.pos, v) < closestDistance {
+				closestDistance = distance(c.pos, v)
+				closestPos = v
+			}
+		}
+	*/
+	// If there are no opportunities, we're done
+	if len(opportunities) == 0 {
+		fmt.Println(c.string(), "sees no opportunities")
+		return true
+	}
+	var bestOpportunities []*complex64
+	moves := make(map[complex64]complex64)
+	bestDist := MaxInt
+	for _, opp := range opportunities {
+		paths := append([]pathPoint{}, pathPoint{
+			pos:   opp,
+			count: 0,
+		})
+		move, length := findMove(c.pos, paths)
+		if length < bestDist {
+			bestOpportunities = append([]*complex64{}, &opp)
+			for k := range moves {
+				delete(moves, k)
+			}
+			moves[opp] = move
+			bestDist = length
+		} else if length == bestDist {
+			bestOpportunities = append(bestOpportunities, &opp)
+			moves[opp] = move
+		}
+	}
+	sort.Sort(ByPos(bestOpportunities))
+	//paths := append([]pathPoint{}, pathPoint{
+	//	pos:   closestPos,
+	//	count: 0,
+	//})
+	//move := findMove(c.pos, paths)
+	if len(bestOpportunities) > 0 {
+		goWith := bestOpportunities[0]
+		fmt.Println(c.string(),
+			"moving to",
+			getCoordString(moves[*goWith]),
+			"(->",
+			getCoordString(*goWith),
+			bestDist, ")")
+		c.moveTo(*goWith)
+	} else {
+		fmt.Println(c.string(), "can't find a path")
+	}
+	// After moving, check for an attack
+	if tPos, err := c.easiestAdjacentTarget(); err == nil {
+		c.attack(tPos)
+	}
+	return c.hasEnemies()
+}
+
+func (c *Character) string() string {
+	return fmt.Sprintf("[%s%s:%d]", string(c.tp), getCoordString(c.pos), c.health)
+}
+
+func (c *Character) attack(p complex64) {
+	fmt.Println(c.string(), "attacks", characters[p].string())
+	characters[p].health -= c.power
+	if characters[p].health <= 0 {
+		c.kills++
+		delete(characters, p)
+		setByte(p, '.')
+	}
+}
+
+func (c *Character) easiestAdjacentTarget() (complex64, error) {
+	var wrk *Character
+	if v, ok := characters[c.pos+DIR_N]; ok && v != nil && v.tp != c.tp {
+		wrk = v
+	}
+	if v, ok := characters[c.pos+DIR_W]; ok && v != nil && v.tp != c.tp {
+		if wrk == nil || v.health < wrk.health {
+			wrk = v
+		}
+	}
+	if v, ok := characters[c.pos+DIR_E]; ok && v != nil && v.tp != c.tp {
+		if wrk == nil || v.health < wrk.health {
+			wrk = v
+		}
+	}
+	if v, ok := characters[c.pos+DIR_S]; ok && v != nil && v.tp != c.tp {
+		if wrk == nil || v.health < wrk.health {
+			wrk = v
+		}
+	}
+	if wrk != nil {
+		return wrk.pos, nil
+	}
+	return 0i, errors.New("No adjacent target")
+}
+
+func (c *Character) isAdjacentTo(p complex64) bool {
+	return c.pos+DIR_N == p || c.pos+DIR_E == p ||
+		c.pos+DIR_S == p || c.pos+DIR_W == p
+}
+
+func (c *Character) getOpenSides() []complex64 {
+	var ret []complex64
+	for _, d := range []complex64{DIR_N, DIR_W, DIR_E, DIR_S} {
+		if getByte(c.pos+d) == '.' {
+			ret = append(ret, c.pos+d)
+		}
+	}
+	return ret
+}
+
+func (c *Character) hasOpenFlank() bool {
+	for _, d := range []complex64{DIR_N, DIR_E, DIR_S, DIR_W} {
+		if getByte(c.pos+d) == '.' {
+			return true
+		}
+	}
+	return false
+}
+
+func (c *Character) move(dir complex64) bool {
+	if getByte(c.pos+dir) != '.' {
+		return false
+	}
+	delete(characters, c.pos)
+	setByte(c.pos, '.')
+	c.pos += dir
+	characters[c.pos] = c
+	setByte(c.pos, c.tp)
+	return true
+}
+
+func (c *Character) moveTo(pos complex64) bool {
+	if getByte(pos) != '.' {
+		return false
+	}
+	delete(characters, c.pos)
+	setByte(c.pos, '.')
+	c.pos = pos
+	characters[c.pos] = c
+	setByte(c.pos, c.tp)
+	return true
+}
+
+func printBattlefield() {
+	//fmt.Print(ClearScreen)
+	for i := 0; i < len(input)/width; i++ {
+		fmt.Println(string(input[i*width : (i+1)*width]))
+	}
+}
+
+func setupBattle() {
+	characters = make(map[complex64]*Character)
+	for i := 0; i < len(input); i++ {
+		pos := getPosFromInt(i)
+		bt := getByte(pos)
+		if bt == 'G' || bt == 'E' {
+			characters[pos] = &Character{
+				tp:     bt,
+				pos:    pos,
+				power:  3,
+				health: 200,
+			}
+			charSlice = append(charSlice, &pos)
+		}
+	}
+}
+
+func isInMap(pos complex64) bool {
+	idx := int(real(pos)) + int(imag(pos))*width
+	return idx >= 0 && idx < len(input)
+}
+
+// getByte pulls a byte from the given position in the input
+func getByte(pos complex64) byte {
+	return input[int(real(pos))+int(imag(pos))*width]
+}
+
+// setByte sets a byte in the input
+func setByte(pos complex64, b byte) {
+	input[int(real(pos))+int(imag(pos))*width] = b
+}
+
+func getPosFromInt(i int) complex64 {
+	return complex(float32(i%width), float32(i/width))
+}
+
+func getCoordString(p complex64) string {
+	return fmt.Sprintf("(%d,%d)", int(real(p)), int(imag(p)))
+}
+
+func stdinToByteSlice() {
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		data := scanner.Bytes()
+		if width == 0 {
+			width = len(data)
+		}
+
+		input = append(input, data...)
+	}
+}
+
+// Returns the next move for the shortest path from p1 to p2
+type pathPoint struct {
+	pos   complex64
+	count int
+}
+
+func findMove(p1 complex64, paths []pathPoint) (complex64, int) {
+	pathCount := len(paths)
+	// First check if p1 has _any_ possible moves
+	lowest := pathPoint{
+		pos:   0 - 1i,
+		count: MaxInt,
+	}
+	for _, v := range paths {
+		for _, d := range []complex64{DIR_N, DIR_E, DIR_S, DIR_W} {
+			wrkPt := pathPoint{
+				pos:   v.pos + d,
+				count: v.count + 1,
+			}
+			if !isInMap(wrkPt.pos) {
+				continue
+			}
+			if wrkPt.pos == p1 {
+				if wrkPt.count < lowest.count {
+					lowest.pos = v.pos
+					lowest.count = v.count
+				}
+			}
+			if getByte(wrkPt.pos) != '.' {
+				continue
+			}
+			var skip bool
+			for _, v2 := range paths {
+				if v2.pos == wrkPt.pos && v2.count <= wrkPt.count {
+					skip = true
+					break
+				}
+			}
+			if skip {
+				continue
+			}
+			paths = append(paths, wrkPt)
+		}
+	}
+	if len(paths) != pathCount && lowest.count == MaxInt {
+		return findMove(p1, paths)
+	}
+	// We hit the end, return the lowest part
+	return lowest.pos, lowest.count
+}
+
+// (Manhattan Distance, thanks earlier day)
+func distance(p1, p2 complex64) int {
+	x1, y1, x2, y2 := real(p1), imag(p1), real(p2), imag(p2)
+	return int(math.Abs(float64(x1)-float64(x2)) + math.Abs(float64(y1)-float64(y2)))
+}
+
+type ByPos []*complex64
+
+func (c ByPos) Len() int      { return len(c) }
+func (c ByPos) Swap(i, j int) { c[i], c[j] = c[j], c[i] }
+func (c ByPos) Less(i, j int) bool {
+	return imag(*c[i]) < imag(*c[j]) ||
+		(imag(*c[i]) == imag(*c[j]) && real(*c[i]) < real(*c[j]))
+}
diff --git a/2018/day15/input b/2018/day15/input
new file mode 100644
index 0000000..10831a4
--- /dev/null
+++ b/2018/day15/input
@@ -0,0 +1,32 @@
+################################
+##########################..####
+#########################...####
+#########################..#####
+########################G..#####
+#####################.#.....##.#
+#####################..........#
+##############.#####...........#
+########G...G#.####............#
+#######......G....#.....#......#
+#######...G....GG.#............#
+#######G.G.............####....#
+#######.#.....#####....E.....###
+#######......#######.G.......###
+#..####..G..#########.###..#####
+#........G..#########.##########
+#..#..#G....#########.##########
+#.###...E...#########.##########
+#####...G.G.#########.##########
+########G....#######..##########
+####..........#####...##########
+####......E........G..##########
+#.G..................###########
+#G...................###########
+###.....##E.......E..###########
+###....#............############
+###.................############
+##G.....#.............##########
+###########...#E..##..##########
+###########.E...###.E.EE.#######
+###########......#.......#######
+################################
diff --git a/2018/day15/testinput1 b/2018/day15/testinput1
new file mode 100644
index 0000000..ac399d6
--- /dev/null
+++ b/2018/day15/testinput1
@@ -0,0 +1,7 @@
+#######
+#G..#E#
+#E#E.E#
+#G.##.#
+#...#E#
+#...E.#
+#######
diff --git a/2018/day15/testinput2 b/2018/day15/testinput2
new file mode 100644
index 0000000..58f778d
--- /dev/null
+++ b/2018/day15/testinput2
@@ -0,0 +1,7 @@
+#######
+#E..EG#
+#.#G.E#
+#E.##E#
+#G..#.#
+#..E#.#
+#######
diff --git a/2018/day15/testinput3 b/2018/day15/testinput3
new file mode 100644
index 0000000..6dc1c08
--- /dev/null
+++ b/2018/day15/testinput3
@@ -0,0 +1,7 @@
+#######
+#E.G#.#
+#.#G..#
+#G.#.G#
+#G..#.#
+#...E.#
+#######
diff --git a/2018/day15/testinput4 b/2018/day15/testinput4
new file mode 100644
index 0000000..2343d7b
--- /dev/null
+++ b/2018/day15/testinput4
@@ -0,0 +1,7 @@
+#######
+#.E...#
+#.#..G#
+#.###.#
+#E#G#G#
+#...#G#
+#######
diff --git a/2018/day15/testinput5 b/2018/day15/testinput5
new file mode 100644
index 0000000..95882b2
--- /dev/null
+++ b/2018/day15/testinput5
@@ -0,0 +1,9 @@
+#########
+#G......#
+#.E.#...#
+#..##..G#
+#...##..#
+#...#...#
+#.G...G.#
+#.....G.#
+#########