Data commit

Task/Find-the-missing-permutation/Julia/find-the-missing-permutation-1.julia

@@ -0,0 +1,13 @@
+using BenchmarkTools, Combinatorics
+
+function missingperm(arr::Vector)
+    allperms = String.(permutations(arr[1]))  # revised for type safety
+    for perm in allperms
+        if perm ∉ arr return perm end
+    end
+end
+
+arr = ["ABCD", "CABD", "ACDB", "DACB", "BCDA", "ACBD", "ADCB", "CDAB", "DABC", "BCAD",
+       "CADB", "CDBA", "CBAD", "ABDC", "ADBC", "BDCA", "DCBA", "BACD", "BADC", "BDAC",
+       "CBDA", "DBCA", "DCAB"]
+@show missingperm(arr)

Task/Find-the-missing-permutation/Julia/find-the-missing-permutation-2.julia

@@ -0,0 +1,12 @@
+function missingperm1(arr::Vector{<:AbstractString})
+    missperm = string()
+    for pos in 1:length(arr[1])
+        s = Set()
+        for perm in arr
+            c = perm[pos]
+            if c ∈ s pop!(s, c) else push!(s, c) end
+        end
+        missperm *= first(s)
+    end
+    return missperm
+end

Task/Find-the-missing-permutation/Julia/find-the-missing-permutation-3.julia

@@ -0,0 +1,16 @@
+function missingperm2(arr::Vector)
+    len = length(arr[1])
+    xorval = zeros(UInt8, len)
+    for perm in [Vector{UInt8}(s) for s in arr], i in 1:len
+        xorval[i] ⊻= perm[i]
+    end
+    return String(xorval)
+end
+
+@show missingperm(arr)
+@show missingperm1(arr)
+@show missingperm2(arr)
+
+@btime missingperm(arr)
+@btime missingperm1(arr)
+@btime missingperm2(arr)