2018 Day 17 Complete!

2018/day17/map.go

@@ -0,0 +1,200 @@
+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+const (
+	springX = 500
+	springY = 0
+)
+const (
+	KindSand = 1 << iota
+	KindClay
+	KindWater
+	KindFlow
+	KindSpring
+	NumKinds
+)
+
+var KindRunes = [NumKinds]rune{
+	KindSand:   '.',
+	KindClay:   '#',
+	KindWater:  '~',
+	KindFlow:   '|',
+	KindSpring: '+',
+}
+
+type Map struct {
+	data    map[int]map[int]int
+	minX    int
+	minY    int
+	maxX    int
+	maxY    int
+	done    bool
+	changed bool
+}
+
+func (m *Map) Set(kind, x, y int) {
+	if m.data[y] == nil {
+		m.data[y] = make(map[int]int)
+	}
+	if m.data[y][x] != kind {
+		m.data[y][x] = kind
+		m.changed = true
+	}
+	if x < m.minX {
+		m.minX = x
+	}
+	if x > m.maxX {
+		m.maxX = x
+	}
+}
+
+func (m *Map) Get(x, y int) int {
+	if m.data[y] == nil {
+		return KindSand
+	}
+	if k, ok := m.data[y][x]; ok {
+		return k
+	}
+	return KindSand
+}
+
+func (m *Map) ParseInput(input []string) {
+	m.minY = math.MaxInt32
+	m.maxY = 0
+	m.minX = math.MaxInt32
+	m.maxX = 0
+
+	m.Set(KindSpring, springX, springY)
+
+	for _, line := range input {
+		var a, b rune
+		var posA, startB, endB int
+		_, err := fmt.Sscanf(line, "%c=%d, %c=%d..%d", &a, &posA, &b, &startB, &endB)
+		if err != nil {
+			panic(err)
+		}
+		if a == 'x' {
+			for y := startB; y <= endB; y++ {
+				m.Set(KindClay, posA, y)
+			}
+			if posA < m.minX {
+				m.minX = posA
+			}
+			if posA > m.maxX {
+				m.maxX = posA
+			}
+			if startB < m.minY {
+				m.minY = startB
+			}
+			if endB > m.maxY {
+				m.maxY = endB
+			}
+		} else {
+			for x := startB; x <= endB; x++ {
+				m.Set(KindClay, x, posA)
+			}
+			if posA < m.minY {
+				m.minY = posA
+			}
+			if posA > m.maxY {
+				m.maxY = posA
+			}
+			if startB < m.minX {
+				m.minX = startB
+			}
+			if endB > m.maxX {
+				m.maxX = endB
+			}
+		}
+	}
+}
+
+func (m *Map) Print() {
+	for y := 0; y <= m.maxY; y++ {
+		for x := m.minX; x <= m.maxX; x++ {
+			fmt.Printf("%c", KindRunes[m.Get(x, y)])
+		}
+		fmt.Println()
+	}
+}
+
+func (m *Map) Count(mask int) int {
+	var sum int
+	for y := m.minY; y <= m.maxY; y++ {
+		for x := m.minX; x <= m.maxX; x++ {
+			if m.Get(x, y)&mask != 0 {
+				sum++
+			}
+		}
+	}
+	return sum
+}
+
+func NewMap(input []string) *Map {
+	m := &Map{}
+	m.data = make(map[int]map[int]int)
+	m.ParseInput(input)
+	return m
+}
+
+type Coordinate struct {
+	X int
+	Y int
+}
+
+func (m *Map) Tick() {
+	m.changed = false
+	for y := 0; y <= m.maxY; y++ {
+		for x := m.minX; x <= m.maxX; x++ {
+			switch m.Get(x, y) {
+			case KindSpring, KindFlow:
+				switch m.Get(x, y+1) {
+				case KindSand:
+					m.Set(KindFlow, x, y+1)
+				case KindClay, KindWater:
+					m.HorizontalFlow(x, y, -1)
+					m.HorizontalFlow(x, y, +1)
+				}
+			case KindClay:
+				m.HorizontalSettle(x+1, y, +1)
+			}
+		}
+	}
+	m.done = !m.changed
+}
+
+func (m *Map) HorizontalSettle(x, y, dir int) bool {
+	if m.Get(x, y) != KindFlow {
+		return false
+	}
+	switch m.Get(x+dir, y) {
+	case KindClay, KindWater:
+		if m.Get(x, y+1)&(KindClay|KindWater) != 0 {
+			m.Set(KindWater, x, y)
+			return true
+		}
+	case KindFlow:
+		if m.HorizontalSettle(x+dir, y, dir) && m.Get(x, y+1)&(KindClay|KindWater) != 0 {
+			m.Set(KindWater, x, y)
+			return true
+		}
+	}
+	return false
+}
+
+func (m *Map) HorizontalFlow(x, y, dir int) {
+	if m.Get(x+dir, y) == KindSand && m.Get(x, y+1)&(KindClay|KindWater) != 0 {
+		m.Set(KindFlow, x+dir, y)
+		m.HorizontalFlow(x+dir, y, dir)
+	}
+}
+
+func (m *Map) Flood() {
+	for !m.done {
+		m.Tick()
+	}
+}