Add solution for day 15

README.md

@@ -17,4 +17,5 @@
 | 11 | 12.206 ms | 85| 817.98 KiB |
 | 12 | 3.904 ms | 4620| 2.33 MiB |
 | 13 | 127.304 μs | 4162| 185.08 KiB |
-| 14 | 63.942 ms | 102832| 83.54 MiB |
+| 14 | 63.942 ms | 102832| 83.54 MiB |
+| 15 | 58.598 ms | 334945| 19.45 MiB |

solutions/2024/src/AdventOfCode24.jl

@@ -8,7 +8,7 @@ module AdventOfCode24
     readInput(day::Int) = AdventOfCode.readInput(day, year)
     export readInput
 
-    solvedDays = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]
+    solvedDays = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
 
     # Include the source files:
     for day in solvedDays

solutions/2024/src/day15.jl

@@ -0,0 +1,137 @@
+module Day15
+    using ..AdventOfCode24
+
+    """
+        day15()
+
+    Solves the two puzzles of day 15. 
+    """
+
+    function day15(input::String = readInput(15))
+        wh, op = split(input, "\n\n")
+        lines = split(wh)
+        op = prod(split(op))
+        grid = [lines[i][j] for i in eachindex(lines), j in eachindex(lines[1])]
+
+        robot = findfirst(==('@'), grid)
+        boxes = findall(==('O'), grid)
+        walls = findall(==('#'), grid)
+
+        robot2 = CartesianIndex(robot, 0)
+        boxes2 = Tuple.(zip(CartesianIndex.(boxes, 0), CartesianIndex.(boxes, 1)))
+        walls2 = CartesianIndex.(walls, 0) ∪ CartesianIndex.(walls, 1)
+
+        for o in op
+            d = directions[o]
+            robot = move_robot(robot, d, boxes, walls)
+
+            d = directions2[o]
+            robot2 = move_robot(robot2, d, boxes2, walls2)
+        end
+
+        s0 = score(boxes)
+        s1 = score(boxes2)
+
+        return [s0, s1]
+
+    end
+
+    import Base.+
+    +(a::CartesianIndex{3}, b::CartesianIndex{3}) = CartesianIndex{3}(a[1]+b[1], a[2]+b[2] + sign(b[3]) * Int(a[3] == b[3] || a[3]+b[3] == -1), mod(a[3]+b[3],2))
+
+    const directions = Dict('>' => CartesianIndex(0, 1), '<' => CartesianIndex(0, -1), '^' => CartesianIndex(-1, 0), 'v' => CartesianIndex(1, 0))
+    const directions2 = Dict('>' => CartesianIndex(0, 0, 1), '<' => CartesianIndex(0, 0, -1), '^' => CartesianIndex(-1, 0, 0), 'v' => CartesianIndex(1, 0, 0))
+
+    function move_robot(robot::CartesianIndex{2}, d::CartesianIndex{2}, boxes::Vector{CartesianIndex{2}}, walls::Vector{CartesianIndex{2}})
+        next = robot + d
+
+        if next in walls
+            return robot
+
+        elseif next in boxes
+            move_boxes(next, d, boxes, walls) ? (return next) : (return robot)
+        else
+            return next
+        end
+    end
+
+    function move_boxes(next::CartesianIndex{2}, d::CartesianIndex{2}, boxes::Vector{CartesianIndex{2}}, walls::Vector{CartesianIndex{2}})
+
+        next_box = next + d
+
+        if next_box in walls 
+            return false
+        elseif next_box in boxes
+            !move_boxes(next_box, d, boxes, walls) && return false
+        end
+
+        i = findfirst(==(next), boxes)
+        boxes[i] += d
+        return true
+
+    end
+
+    function move_robot(robot::CartesianIndex{3}, d::CartesianIndex{3}, boxes::Vector{Tuple{CartesianIndex{3},CartesianIndex{3}}}, walls::Vector{CartesianIndex{3}})
+        next = robot + d
+
+        if next in walls
+            return robot
+        elseif any(in.(next, boxes))
+            iboxes = move_boxes(next, d, boxes, walls) 
+
+            isnothing(iboxes) && (return robot)
+
+            for (i, b) in iboxes
+                boxes[i] = b
+            end
+
+            return next
+
+        else
+            return next
+        end
+
+    end
+
+    function move_boxes(next::CartesianIndex{3}, d::CartesianIndex{3}, boxes::Vector{Tuple{CartesianIndex{3},CartesianIndex{3}}}, walls::Vector{CartesianIndex{3}})
+
+        i = findfirst(in.(next, boxes))
+        box = boxes[i]
+        next_boxes = (box[1]+d, box[2]+d)
+
+        x = []
+        for b in next_boxes
+
+            if b in walls 
+                return 
+            elseif !(b in box) && any(in.(b, boxes))
+                iboxes = move_boxes(b, d, boxes, walls)
+                isnothing(iboxes) && return
+                union!(x, iboxes)
+            end
+
+        end
+
+        return union!(x, [(i, next_boxes)])
+
+    end
+
+    function score(boxes::Vector{CartesianIndex{2}})
+        s = 0
+        for b in boxes
+            s += 100*(b[1]-1)+(b[2]-1)
+        end
+
+        return s
+    end
+
+    function score(boxes::Vector{Tuple{CartesianIndex{3}, CartesianIndex{3}}})
+        s = 0
+        for (b,_) in boxes
+            s += 100*(b[1]-1)+2*(b[2]-1)+b[3]
+        end
+
+        return s
+    end
+
+end 

solutions/2024/test/runtests.jl

@@ -54,3 +54,7 @@ end
 @testset "Day 14" begin
     @test AdventOfCode24.Day14.day14() == [230436441, 8270]
 end
+
+@testset "Day 15" begin
+    @test AdventOfCode24.Day15.day15() == [1514353, 1533076]
+end