diff --git a/c-gaps/credit.c b/c-gaps/credit.c
index 2a60e39..3fc3adc 100644
--- a/c-gaps/credit.c
+++ b/c-gaps/credit.c
@@ -2,8 +2,96 @@
 #include <lauxlib.h>
 
 // implement it here
+#include <stdlib.h>
 
+
+int clear_gaps(lua_State* L)
+{
+	luaL_argcheck(L, lua_istable(L, -1), -1, "Error, table_required\n");
+	
+	size_t table_len = lua_objlen(L, -1);
+	
+	if ( table_len == 0)
+	{
+		lua_newtable(L);
+		return 1;
+	}
+
+	const char** in_table = (const char**)malloc(sizeof(char*) * table_len);
+
+	// get first string
+	size_t f_size;
+	lua_rawgeti(L, 1, 1);
+	in_table[0] = luaL_checklstring(L, -1, &f_size);
+	lua_pop(L, 1);
+
+	//lua_istable
+	
+	int i = 2;
+	for (; i <= table_len; i++)
+	{
+		size_t str_size;
+		lua_rawgeti(L, 1, i);
+
+		in_table[i - 1] = luaL_checklstring(L, -1, &str_size);
+		lua_pop(L, 1);
+
+		luaL_argcheck(L, str_size == f_size, -1, "Error, sequences must have the same length\n");
+	}
+
+	// create place for out table
+	char** out_table = (char**)malloc(sizeof(char*) * table_len);
+	for (i = 0; i < table_len; i++)
+	{
+		out_table[i] = (char*)malloc(sizeof(char) * f_size);
+	}
+
+	int j = 0;
+	size_t new_size = 0;
+
+	// delete only gaps columns
+	for (; j < f_size; j++)
+	{
+		char only_gaps = 1;
+		for (i = 0; i < table_len; i++)
+		{
+			if (in_table[i][j] != '-')
+			{
+				only_gaps = 0;
+			}
+		}
+
+
+		if (! only_gaps) 
+		{
+			for (i = 0; i < table_len; i++)
+			{
+				out_table[i][new_size] = in_table[i][j];
+			}
+			new_size++;
+		}
+	}
+
+	
+	lua_newtable(L); // create lua table
+
+	for (i = 0; i < table_len; i++)
+	{
+		lua_pushlstring(L, out_table[i], new_size);
+		lua_rawseti(L, -2, i + 1);
+	}
+
+	// free memory
+	
+	for (i = 0; i < table_len; i++)
+	{
+		free(out_table[i]);
+	}
+	free(in_table);
+	free(out_table);
+	return 1; // function returns one argument
+}
 int luaopen_gaps(lua_State* L) {
-    // return it here
-    return 0;
+	lua_pushcfunction(L, clear_gaps);
+	return 1;
 }
diff --git a/c-gaps/spec.lua b/c-gaps/spec.lua
index 2129000..498c005 100644
--- a/c-gaps/spec.lua
+++ b/c-gaps/spec.lua
@@ -1,9 +1,9 @@
 describe("gaps (implementation)", function()
-    pending("loads module", function()
+    it("loads module", function()
         local f = require 'gaps'
     end)
 
-    pending("doesn't change good alignment", function()
+    it("doesn't change good alignment", function()
         local f = require 'gaps'
         assert.same({}, f({}))
         assert.same({''}, f({''}))
@@ -14,7 +14,7 @@ describe("gaps (implementation)", function()
         assert.same({'A'}, f({'A-'}))
     end)
 
-    pending("removes gap columns", function()
+    it("removes gap columns", function()
         local f = require 'gaps'
         assert.same({''}, f({'-'}))
         assert.same({'', ''}, f({'-', '-'}))
@@ -30,7 +30,7 @@ describe("gaps (implementation)", function()
         }))
     end)
 
-    pending("throws error if input is not table",
+    it("throws error if input is not table",
     function()
         local f = require 'gaps'
         assert.has_error(function()
@@ -41,7 +41,7 @@ describe("gaps (implementation)", function()
         end)
     end)
 
-    pending("throws error if table members are not strings",
+    it("throws error if table members are not strings",
     function()
         local f = require 'gaps'
         assert.has_error(function()
@@ -49,7 +49,7 @@ describe("gaps (implementation)", function()
         end)
     end)
 
-    pending("throws error if strings' lengths differ",
+    it("throws error if strings' lengths differ",
     function()
         local f = require 'gaps'
         assert.has_error(function()
diff --git a/lua-shuf/credit.lua b/lua-shuf/credit.lua
index 068643b..efaba4e 100644
--- a/lua-shuf/credit.lua
+++ b/lua-shuf/credit.lua
@@ -1,5 +1,39 @@
 local function g(f)
-    -- implement it here
+	local n = 1000
+	local occurense = {}
+	for i = 1, n do
+		occurense[i] = 0
+	end
+	local result = f(n)
+
+	assert(type(result) == "table")
+	assert(#result == n)
+	for i = 1, n do
+		occurense[result[i]] = 1
+	end
+	
+	local sum = 0
+	for i = 1, n do
+		sum = sum + occurense[i]
+	end
+	assert(sum == n)
+
+	local len = 0
+	for k, y in pairs(result) do
+		len = len + 1
+	end
+
+	assert(len == n) 
+
+	assert(not pcall(function()
+		f('sdads')
+	end))
+	assert(not pcall(function()
+		f('1ddd')
+	end))
+	assert(not pcall(function()
+		f({0})
+	end))
 end
 
 return g
diff --git a/lua-shuf/spec.lua b/lua-shuf/spec.lua
index be744df..467fa47 100644
--- a/lua-shuf/spec.lua
+++ b/lua-shuf/spec.lua
@@ -40,32 +40,32 @@ local function shufRangeBad3(n)
 end
 
 describe("shuf (unit test)", function()
-    pending("loads module", function()
+    it("loads module", function()
         local g = require 'shuf.credit'
     end)
 
-    pending("accepts good shufRange", function()
+    it("accepts good shufRange", function()
         local g = require 'shuf.credit'
         assert.has_no_error(function()
             g(shufRange)
         end)
     end)
 
-    pending("don't accept bad shufRangeBad", function()
+    it("don't accept bad shufRangeBad", function()
         local g = require 'shuf.credit'
         assert.has_error(function()
             g(shufRangeBad)
         end)
     end)
 
-    pending("don't accept bad shufRangeBad2", function()
+    it("don't accept bad shufRangeBad2", function()
         local g = require 'shuf.credit'
         assert.has_error(function()
             g(shufRangeBad2)
         end)
     end)
 
-    pending("don't accept bad shufRangeBad3", function()
+    it("don't accept bad shufRangeBad3", function()
         local g = require 'shuf.credit'
         assert.has_error(function()
             g(shufRangeBad3)