Data commit

Task/Permutations-by-swapping/Julia/permutations-by-swapping-1.julia

@@ -0,0 +1,58 @@
+function johnsontrottermove!(ints, isleft)
+    len = length(ints)
+    function ismobile(pos)
+        if isleft[pos] && (pos > 1) && (ints[pos-1] < ints[pos])
+            return true
+        elseif !isleft[pos] && (pos < len) && (ints[pos+1] < ints[pos])
+            return true
+        end
+        false
+    end
+    function maxmobile()
+        arr = [ints[pos] for pos in 1:len if ismobile(pos)]
+        if isempty(arr)
+            0, 0
+        else
+            maxmob = maximum(arr)
+            maxmob, findfirst(x -> x == maxmob, ints)
+        end
+    end
+    function directedswap(pos)
+        tmp = ints[pos]
+        tmpisleft = isleft[pos]
+        if isleft[pos]
+            ints[pos] = ints[pos-1]; ints[pos-1] = tmp
+            isleft[pos] = isleft[pos-1]; isleft[pos-1] = tmpisleft
+        else
+            ints[pos] = ints[pos+1]; ints[pos+1] = tmp
+            isleft[pos] = isleft[pos+1]; isleft[pos+1] = tmpisleft
+        end
+    end
+    (moveint, movepos) = maxmobile()
+    if movepos > 0
+        directedswap(movepos)
+        for (i, val) in enumerate(ints)
+            if val > moveint
+                isleft[i] = !isleft[i]
+            end
+        end
+        ints, isleft, true
+    else
+        ints, isleft, false
+    end
+end
+function johnsontrotter(low, high)
+    ints = collect(low:high)
+    isleft = [true for i in ints]
+    firstconfig = copy(ints)
+    iters = 0
+    while true
+        iters += 1
+        println("$ints $(iters & 1 == 1 ? "+1" : "-1")")
+        if johnsontrottermove!(ints, isleft)[3] == false
+            break
+        end
+    end
+    println("There were $iters iterations.")
+end
+johnsontrotter(1,4)

Task/Permutations-by-swapping/Julia/permutations-by-swapping-2.julia

@@ -0,0 +1,23 @@
+function johnsontrotter(low, high)
+    function permutelevel(vec)
+        if length(vec) < 2
+            return [vec]
+        end
+        sequences = []
+        endint = vec[end]
+        smallersequences = permutelevel(vec[1:end-1])
+        leftward = true
+        for seq in smallersequences
+            for pos in (leftward ? (length(seq)+1:-1:1): (1:length(seq)+1))
+                push!(sequences, insert!(copy(seq), pos, endint))
+            end
+            leftward = !leftward
+        end
+        sequences
+    end
+    permutelevel(collect(low:high))
+end
+
+for (i, sequence) in enumerate(johnsontrotter(1,4))
+    println("""$sequence, $(i & 1 == 1 ? "+1" : "-1")""")
+end