Add solution for day 9

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]
+    solvedDays = [1, 2, 3, 4, 5, 6, 7, 8, 9]
 
     # Include the source files:
     for day in solvedDays

solutions/2024/src/day09.jl

@@ -0,0 +1,140 @@
+module Day09
+    using ..AdventOfCode24
+
+    """
+        day09()
+
+    Solves the two puzzles of day 09. 
+    """
+
+    function day09(input::String = readInput(09))
+        disk =  [parse(Int, m) for m in input]
+
+        maxid = floor(Int, length(disk)/2)
+        ids = Dict{Int, Int}(k-1 => m for (k,m) in enumerate(disk[1:2:end]) )
+        gaps = Dict{Int, Vector{Int}}( k-1 => [m] for (k,m) in enumerate(disk[2:2:end]) )
+        gaps[maxid] = [0]
+
+        ids1 = deepcopy(ids)
+        gaps1 = deepcopy(gaps)
+
+        d = Int[]
+        d1 = Int[]
+        for k in 0:maxid
+           fill_id!(d, ids, k)
+           fill_id!(d1, ids1, k)
+
+            fill_gaps0!(d, ids, gaps, k)
+            fill_gaps1!(d1, ids1, gaps1, k)
+        end 
+
+        s0 = checksum(d)
+        s1 = checksum(d1)
+
+        return [s0,s1]
+    end
+
+    function checksum(d::Vector{Int})
+        s = 0
+        for (k,m) in enumerate(d)
+            (m >= 0) && (s += (k-1) * m)
+        end
+
+        return s
+    end
+
+    function fill_id!(d::Vector{Int}, ids::Dict{Int, Int}, k::Int)
+
+        !haskey(ids, k) && return
+
+        for _ in 1:ids[k]
+            push!(d, k)
+        end
+
+        delete!(ids, k)
+
+    end
+
+    function fill_gaps1!(d::Vector{Int}, ids::Dict{Int, Int}, gaps::Dict{Int, Vector{Int}}, k::Int)
+
+        for g in gaps[k]
+            l = g
+
+            while true
+                l == 0 && break
+                l_old = l
+
+                for k in maxid:-1:1
+                    !haskey(ids, k) && continue
+
+                    if l >= ids[k]
+
+                        l = l-ids[k]
+
+                        for _ in 1:ids[k]
+                            push!(d, k)
+                        end
+
+                        pushfirst!(gaps[k], ids[k])
+
+                        delete!(ids, k)
+
+                        break
+                    end
+
+                end
+
+                if l == l_old 
+                    for _ in 1:l
+                        push!(d, -1)
+                    end
+
+                    break
+                end
+            end
+
+        end
+
+
+    end
+
+    function fill_gaps0!(d::Vector{Int}, ids::Dict{Int, Int}, gaps::Dict{Int, Vector{Int}}, k::Int)
+
+        for g in gaps[k]
+            l = g  
+            while l > 0 && !isempty(ids)
+
+                for k in maxid:-1:1
+                    !haskey(ids, k) && continue
+
+                    if l >= ids[k]
+
+                        l = l-ids[k]
+
+                        for _ in 1:ids[k]
+                            push!(d, k)
+                        end
+
+                        delete!(ids, k)
+
+                        break
+                    else
+
+                        for _ in 1:l
+                            push!(d, k)
+                        end
+
+                        ids[k] -= l                        
+                        l = 0
+                        break
+                    end
+                end
+
+            end
+
+        end
+
+    end
+
+end 
+

solutions/2024/test/runtests.jl

@@ -30,3 +30,7 @@ end
 @testset "Day 08" begin
     @test AdventOfCode24.Day08.day08() == [390, 1246]
 end
+
+@testset "Day 09" begin
+    @test AdventOfCode24.Day09.day09() == [6378826667552, 6413328569890]
+end