Merge pull request JuliaLang#25 from andrej-makarov-skrt/ex-secret-ha…

…ndshake

Add exercise: secret-handshake

config.json

@@ -53,8 +53,8 @@
       "difficulty": 1,
       "topics": [
         "control-flow (conditionals)",
-				"integers",
-				"mathematics"
+        "integers",
+		"mathematics"
       ]
     },
     {
@@ -105,6 +105,15 @@
         "integers",
         "mathematics"
       ]
+    },
+    {
+      "slug": "secret-handshake",
+      "difficulty": 2,
+      "topics": [
+        "arrays",
+        "filtering",
+        "mathematics"
+      ]
     }
   ],
   "deprecated": [

exercises/secret-handshake/example.jl

@@ -0,0 +1,12 @@
+function secret_handshake(code::Integer)
+    # NOTE: Handle wrong codes
+    # code < 0 && error("Invalid secret handshake code")
+    # NOTE: Handle common actions
+    masks = [(1, "wink"), (2, "double blink"),
+             (4, "close your eyes"), (8, "jump")]
+    actions = map(x->code&x[1]==x[1]&&x[2], masks)
+    filter!(x->x!=false, actions)
+    # NOTE: Handle reversing bitmask
+    code&16==16 && reverse!(actions)
+    actions
+end

exercises/secret-handshake/runtests.jl

@@ -0,0 +1,51 @@
+using Base.Test
+
+include("secret-handshake.jl")
+
+@testset "wink for 1" begin
+    @test secret_handshake(1) == ["wink"]
+end
+
+@testset "double blink for 10" begin
+    @test secret_handshake(2) == ["double blink"]
+end
+
+@testset "close your eyes for 100" begin
+    @test secret_handshake(4) == ["close your eyes"]
+end
+
+@testset "jump for 1000" begin
+    @test secret_handshake(8) == ["jump"]
+end
+
+@testset "combine two actions" begin
+    @test secret_handshake(3) == ["wink", "double blink"]
+end
+
+@testset "reverse two actions" begin
+    @test secret_handshake(19) == ["double blink", "wink"]
+end
+
+@testset "reversing one action gives the same action" begin
+    @test secret_handshake(24) == ["jump"]
+end
+
+@testset "reversing no actions still gives no actions" begin
+    @test secret_handshake(16) == []
+end
+
+@testset "all possible actions" begin
+    @test secret_handshake(15) == ["wink", "double blink", "close your eyes", "jump"]
+end
+
+@testset "reverse all possible actions" begin
+    @test secret_handshake(31) == ["jump", "close your eyes", "double blink", "wink"]
+end
+
+@testset "do nothing for zero" begin
+    @test secret_handshake(0) == []
+end
+
+@testset "do nothing if lower 5 bits not set" begin
+    @test secret_handshake(32) == []
+end

exercises/secret-handshake/secret-handshake.jl

@@ -0,0 +1,3 @@
+function secret_handshake(code::Integer)
+
+end