2023 Day 14 Complete!

2023/day14/main.go

@@ -0,0 +1,128 @@
+package main
+
+import (
+	"fmt"
+
+	h "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+func main() {
+	inp := h.StdinToStringSlice()
+	part1(inp)
+	fmt.Println()
+	part2(inp)
+}
+
+func part1(input []string) {
+	m := h.StringSliceToCoordByteMap(input)
+	fmt.Println("# Part 1")
+	tiltNorth(&m)
+	fmt.Println(calcLoad(&m))
+}
+
+func part2(input []string) {
+	target := 1_000_000_000
+	mapCache := make(map[string]int)
+	m := h.StringSliceToCoordByteMap(input)
+	var i = 0
+	var ignoreCache bool
+	for ; i <= target; i++ {
+		tiltNorth(&m)
+		tiltWest(&m)
+		tiltSouth(&m)
+		tiltEast(&m)
+		if !ignoreCache {
+			if v, ok := mapCache[m.String()]; ok && i > 200 {
+				target = i + (target-v)%(i-v) - 1
+				ignoreCache = true
+			}
+			mapCache[m.String()] = i
+		}
+	}
+	fmt.Println("# Part 2")
+	fmt.Println(calcLoad(&m))
+}
+
+func c(x, y int) h.Coordinate { return h.Coordinate{X: x, Y: y} }
+
+// m.FindAll returns a slice sorted Left->Right, Top->Bottom
+func tiltNorth(m *h.CoordByteMap) {
+	rocks := m.FindAll('O')
+	for i := range rocks {
+		if rocks[i].Y == m.TLY {
+			continue
+		}
+		mv := h.Coordinate{X: rocks[i].X, Y: rocks[i].Y}
+		for m.Get(mv.North()) == '.' {
+			mv.MoveNorth()
+		}
+		if !mv.Equals(rocks[i]) {
+			m.Put(rocks[i], '.')
+			m.Put(mv, 'O')
+		}
+	}
+}
+func tiltEast(m *h.CoordByteMap) {
+	rocks := m.FindAll('O')
+	for i, j := 0, len(rocks)-1; i < j; i, j = i+1, j-1 {
+		rocks[i], rocks[j] = rocks[j], rocks[i]
+	}
+	for i := range rocks {
+		if rocks[i].X == m.BRX {
+			continue
+		}
+		mv := h.Coordinate{X: rocks[i].X, Y: rocks[i].Y}
+		for m.Get(mv.East()) == '.' {
+			mv.MoveEast()
+		}
+		if !mv.Equals(rocks[i]) {
+			m.Put(rocks[i], '.')
+			m.Put(mv, 'O')
+		}
+	}
+}
+func tiltSouth(m *h.CoordByteMap) {
+	rocks := m.FindAll('O')
+	for i, j := 0, len(rocks)-1; i < j; i, j = i+1, j-1 {
+		rocks[i], rocks[j] = rocks[j], rocks[i]
+	}
+	for i := range rocks {
+		if rocks[i].Y == m.BRY {
+			continue
+		}
+		mv := h.Coordinate{X: rocks[i].X, Y: rocks[i].Y}
+		for m.Get(mv.South()) == '.' {
+			mv.MoveSouth()
+		}
+		if !mv.Equals(rocks[i]) {
+			m.Put(rocks[i], '.')
+			m.Put(mv, 'O')
+		}
+	}
+}
+func tiltWest(m *h.CoordByteMap) {
+	rocks := m.FindAll('O')
+	for i := range rocks {
+		if rocks[i].X == m.TLX {
+			continue
+		}
+		mv := h.Coordinate{X: rocks[i].X, Y: rocks[i].Y}
+		for m.Get(mv.West()) == '.' {
+			mv.MoveWest()
+		}
+		if !mv.Equals(rocks[i]) {
+			m.Put(rocks[i], '.')
+			m.Put(mv, 'O')
+		}
+	}
+}
+
+func calcLoad(m *h.CoordByteMap) int {
+	var res int
+	bot := m.BRY
+	rocks := m.FindAll('O')
+	for i := range rocks {
+		res += (bot - rocks[i].Y) + 1
+	}
+	return res
+}