Day III

day03/Project.toml

@@ -0,0 +1,4 @@
+name = "day03"
+uuid = "fcc5b334-7230-44ca-b424-8172184a1b5b"
+authors = ["HeNine "]
+version = "0.1.0"

day03/data/case00.txt

@@ -0,0 +1,12 @@
+00100
+11110
+10110
+10111
+10101
+01111
+00111
+11100
+10000
+11001
+00010
+01010

day03/src/day03.jl

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+function task0(file)
+
+    sums = missing
+
+    nrows = 0
+
+    for line in eachline(file)
+        nrows += 1
+        bits = split(line, "") .|> x -> parse(Int, x)
+
+        if sums === missing
+            sums = bits
+        else
+            sums += bits
+        end
+    end
+
+    (sums .> nrows / 2)' * [2^i for i = (length(sums)-1):-1:0] *
+    (sums .< nrows / 2)' * [2^i for i = (length(sums)-1):-1:0]
+end
+
+##
+
+println("Day 03 – Task 1 – Case 0")
+open(task0, "day03\\data\\case00.txt") |> println
+
+println("Day 03 – Task 1 – Case 1")
+open(task0, "day03\\data\\case01.txt") |> println
+
+##
+
+function task1(file)
+    bitvectors = eachline(file) .|>
+                 line -> split(line, "") .|>
+                         x -> parse(Int, x)
+
+    findval(1, bitvectors) *
+    findval(0, bitvectors)
+end
+
+function findval(gas, bitvectors, pos = 1)
+    if length(bitvectors) == 1
+        return bitvectors[1]' * [2^i for i = (length(bitvectors[1])-1):-1:0]
+    end
+
+    sums = reduce(+, bitvectors)
+    nrow = length(bitvectors)
+
+    findval(gas,
+        filter(
+            x ->
+                x[pos] == ((gas == 1 && sums[pos] >= nrow / 2) || (gas == 0 && sums[pos] < nrow / 2)),
+            bitvectors
+        ),
+        pos + 1)
+end
+
+##
+
+println("Day 03 – Task 1 – Case 0")
+open(task1, "day03\\data\\case00.txt") |> println
+
+println("Day 03 – Task 1 – Case 1")
+open(task1, "day03\\data\\case01.txt") |> println