Create dependencies exercise

17_prime_factors.lua

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+-- Write a function which determines the prime factors of a given
+-- number, returning them in a list.  You may assume that none of the
+-- prime factors are above 10000
+--
+-- Solution --------------------------------------------------------------------
+function prime_factors(n)
+	-- Your implementation here
+end
+
+-- Tests -----------------------------------------------------------------------
+
+local luaunit = require("luaunit.luaunit")
+
+function test_prime_factors_of_42()
+	luaunit.assertItemsEquals(prime_factors(42), {2, 3, 7})
+end
+
+function test_prime_factors_of_70()
+	luaunit.assertItemsEquals(prime_factors(70), {2, 5, 7})
+end
+
+function test_prime_factors_of_253()
+	luaunit.assertItemsEquals(prime_factors(253), {11, 23})
+end
+
+function test_prime_factors_of_245()
+	luaunit.assertItemsEquals(prime_factors(245), {5, 7, 7})
+end
+
+function test_prime_factors_of_36()
+	luaunit.assertItemsEquals(prime_factors(36), {2, 2, 3, 3})
+end
+
+function test_prime_factors_of_1337()
+	luaunit.assertItemsEquals(prime_factors(1337), {7, 191})
+end
+
+function test_prime_factors_of_4321()
+	luaunit.assertItemsEquals(prime_factors(4321), {29, 149})
+end
+
+function test_prime_factors_of_57812834()
+	luaunit.assertItemsEquals(prime_factors(57812834), {2, 29, 113, 8821})
+end
+
+function test_prime_factors_of_8894220()
+	luaunit.assertItemsEquals(prime_factors(8894220), {2, 2, 3, 5, 271, 547})
+end
+
+os.exit(luaunit.LuaUnit.run())

19_dependencies.lua

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+-- Write a function to generate a valid order for a number of jobs
+-- that depend upon each other.  Your input is a jobs table; each key
+-- is a job number, with its the values being a list jobs it depends
+-- on.  You may assume that there are no circular dependencies.
+--
+-- Return a list of job numbers, so that performing the jobs in that
+-- order ensures that all jobs are exactly once, and all dependencies
+-- of a job are done before prior to it.
+--
+-- Solution --------------------------------------------------------------------
+function schedule(jobs)
+	-- Your implementation here
+end
+
+-- Tests -----------------------------------------------------------------------
+
+local luaunit = require("luaunit.luaunit")
+
+local function keys(t)
+	local results = {}
+	for key, _ in pairs(t) do table.insert(results, key) end
+	return results
+end
+
+local function contains(list, target)
+	for _, item in ipairs(list) do if item == target then return true end end
+	return false
+end
+
+local function deep_copy(original)
+	local copy = {}
+	if type(original) == "table" then
+		for key, value in pairs(original) do
+			local key_copy = deep_copy(key)
+			local value_copy = deep_copy(value)
+			copy[key_copy] = value_copy
+		end
+	else
+		copy = original
+	end
+	return copy
+end
+
+local function assert_valid(order, jobs)
+	local done = {}
+	for _, job in ipairs(order) do
+		for _, dependency in ipairs(jobs[job]) do
+			luaunit.assertTrue(contains(done, dependency))
+		end
+		table.insert(done, job)
+	end
+end
+
+local function test_case(jobs)
+	local order = schedule(deep_copy(jobs))
+	luaunit.assertItemsEquals(order, keys(jobs))
+	assert_valid(order, jobs)
+end
+
+function test_sequential_dependencies()
+	local jobs = {[1] = {2}, [2] = {3}, [3] = {}}
+	test_case(jobs)
+end
+
+function test_converging_dependencies()
+	local jobs = {
+		[1] = {5},
+		[2] = {5},
+		[3] = {6},
+		[4] = {6},
+		[5] = {7},
+		[6] = {7},
+		[7] = {},
+	}
+	test_case(jobs)
+end
+
+function test_diverging_dependencies()
+	local jobs = {
+		[1] = {2, 3},
+		[2] = {4, 5},
+		[3] = {6, 7},
+		[4] = {},
+		[5] = {},
+		[6] = {},
+		[7] = {}
+	}
+	test_case(jobs)
+end
+
+function test_compound_dependencies()
+	local jobs = {
+		[1] = {2, 3, 4},
+		[2] = {5, 6},
+		[3] = {7},
+		[4] = {7},
+		[5] = {},
+		[6] = {8},
+		[7] = {8},
+		[8] = {}
+	}
+	test_case(jobs)
+end
+
+os.exit(luaunit.LuaUnit.run())