diff --git a/lua/cp/config.lua b/lua/cp/config.lua
index 5860363..1bbda23 100644
--- a/lua/cp/config.lua
+++ b/lua/cp/config.lua
@@ -20,15 +20,7 @@ M.defaults = {
 }
 
 local function extend_contest_config(base_config, contest_config)
-	local result = vim.deepcopy(base_config)
-
-	for key, value in pairs(contest_config) do
-		if key == "compile_flags" or key == "debug_flags" then
-			vim.list_extend(result[key], value)
-		else
-			result[key] = value
-		end
-	end
+	local result = vim.tbl_deep_extend("force", base_config, contest_config)
 
 	local std_flag = ("-std=c++%d"):format(result.cpp_version)
 	table.insert(result.compile_flags, 1, std_flag)
diff --git a/lua/cp/execute.lua b/lua/cp/execute.lua
new file mode 100644
index 0000000..f4d0d78
--- /dev/null
+++ b/lua/cp/execute.lua
@@ -0,0 +1,111 @@
+local M = {}
+
+local signal_codes = {
+	[128] = "SIGILL",
+	[130] = "SIGABRT",
+	[131] = "SIGBUS",
+	[136] = "SIGFPE",
+	[135] = "SIGSEGV",
+	[137] = "SIGPIPE",
+	[139] = "SIGTERM",
+}
+
+local function get_paths(problem_id)
+	return {
+		source = ("%s.cc"):format(problem_id),
+		binary = ("build/%s"):format(problem_id),
+		input = ("io/%s.in"):format(problem_id),
+		output = ("io/%s.out"):format(problem_id),
+		expected = ("io/%s.expected"):format(problem_id),
+	}
+end
+
+local function ensure_directories()
+	vim.system({ "mkdir", "-p", "build", "io" }):wait()
+end
+
+local function compile_cpp(source_path, binary_path, flags)
+	local compile_cmd = { "g++", unpack(flags), source_path, "-o", binary_path }
+	return vim.system(compile_cmd, { text = true }):wait()
+end
+
+local function execute_binary(binary_path, input_data, timeout_ms)
+	local start_time = vim.loop.hrtime()
+
+	local result = vim.system({ binary_path }, {
+		stdin = input_data,
+		timeout = timeout_ms,
+		text = true,
+	}):wait()
+
+	local end_time = vim.loop.hrtime()
+	local execution_time = (end_time - start_time) / 1000000
+
+	return {
+		stdout = result.stdout or "",
+		stderr = result.stderr or "",
+		code = result.code,
+		time_ms = execution_time,
+		timed_out = result.code == 124,
+	}
+end
+
+local function format_output(exec_result, expected_file)
+	local lines = { exec_result.stdout }
+
+	if exec_result.timed_out then
+		table.insert(lines, "\n[code]: 124 (TIMEOUT)")
+	elseif exec_result.code >= 128 then
+		local signal_name = signal_codes[exec_result.code] or "SIGNAL"
+		table.insert(lines, ("\n[code]: %d (%s)"):format(exec_result.code, signal_name))
+	else
+		table.insert(lines, ("\n[code]: %d"):format(exec_result.code))
+	end
+
+	table.insert(lines, ("\n[time]: %.2f ms"):format(exec_result.time_ms))
+	table.insert(lines, "\n[debug]: false")
+
+	if vim.fn.filereadable(expected_file) == 1 and exec_result.code == 0 then
+		local expected_content = vim.fn.readfile(expected_file)
+		local actual_lines = vim.split(exec_result.stdout, "\n")
+
+		local matches = #actual_lines == #expected_content
+		if matches then
+			for i, line in ipairs(actual_lines) do
+				if line ~= expected_content[i] then
+					matches = false
+					break
+				end
+			end
+		end
+
+		table.insert(lines, ("\n[matches]: %s"):format(matches and "true" or "false"))
+	end
+
+	return table.concat(lines, "")
+end
+
+function M.run_problem(problem_id, contest_config, is_debug)
+	ensure_directories()
+
+	local paths = get_paths(problem_id)
+	local flags = is_debug and contest_config.debug_flags or contest_config.compile_flags
+
+	local compile_result = compile_cpp(paths.source, paths.binary, flags)
+	if compile_result.code ~= 0 then
+		vim.fn.writefile({ compile_result.stderr }, paths.output)
+		return
+	end
+
+	local input_data = ""
+	if vim.fn.filereadable(paths.input) == 1 then
+		input_data = table.concat(vim.fn.readfile(paths.input), "\n") .. "\n"
+	end
+
+	local exec_result = execute_binary(paths.binary, input_data, contest_config.timeout_ms)
+	local formatted_output = format_output(exec_result, paths.expected)
+
+	vim.fn.writefile(vim.split(formatted_output, "\n"), paths.output)
+end
+
+return M
diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index fb73e63..09a1dc4 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -1,5 +1,7 @@
 local config_module = require("cp.config")
 local snippets = require("cp.snippets")
+local execute = require("cp.execute")
+local scrape = require("cp.scrape")
 
 local M = {}
 local config = {}
@@ -40,9 +42,9 @@ local function setup_python_env()
 
 	if vim.fn.isdirectory(venv_dir) == 0 then
 		log("setting up Python environment for scrapers...")
-		local result = vim.fn.system(("cd %s && uv sync"):format(vim.fn.shellescape(plugin_path)))
-		if vim.v.shell_error ~= 0 then
-			log("failed to setup Python environment: " .. result, vim.log.levels.ERROR)
+		local result = vim.system({ "uv", "sync" }, { cwd = plugin_path, text = true }):wait()
+		if result.code ~= 0 then
+			log("failed to setup Python environment: " .. result.stderr, vim.log.levels.ERROR)
 			return false
 		end
 		log("python environment setup complete")
@@ -63,8 +65,8 @@ local function setup_contest(contest_type)
 	end
 
 	vim.g.cp_contest = contest_type
-	vim.fn.system(("cp -fr %s/* ."):format(config.template_dir))
-	vim.fn.system(("make setup VERSION=%s"):format(config.contests[contest_type].cpp_version))
+	vim.fn.mkdir("build", "p")
+	vim.fn.mkdir("io", "p")
 	log(("set up %s contest environment"):format(contest_type))
 end
 
@@ -89,17 +91,24 @@ local function setup_problem(problem_id, problem_letter)
 
 	vim.cmd.only()
 
-	local filename, full_problem_id
-	if (vim.g.cp_contest == "atcoder" or vim.g.cp_contest == "codeforces") and problem_letter then
-		full_problem_id = problem_id .. problem_letter
-		filename = full_problem_id .. ".cc"
-		vim.fn.system(("make scrape %s %s %s"):format(vim.g.cp_contest, problem_id, problem_letter))
+	local scrape_result = scrape.scrape_problem(vim.g.cp_contest, problem_id, problem_letter)
+
+	if not scrape_result.success then
+		log("scraping failed: " .. scrape_result.error, vim.log.levels.WARN)
+		log("you can manually add test cases to io/ directory", vim.log.levels.INFO)
 	else
-		full_problem_id = problem_id
-		filename = problem_id .. ".cc"
-		vim.fn.system(("make scrape %s %s"):format(vim.g.cp_contest, problem_id))
+		log(("scraped %d test case(s) for %s"):format(scrape_result.test_count, scrape_result.problem_id))
 	end
 
+	local full_problem_id = scrape_result.success and scrape_result.problem_id
+		or (
+			(vim.g.cp_contest == "atcoder" or vim.g.cp_contest == "codeforces")
+				and problem_letter
+				and problem_id .. problem_letter:upper()
+			or problem_id
+		)
+	local filename = full_problem_id .. ".cc"
+
 	vim.cmd.e(filename)
 
 	if vim.api.nvim_buf_get_lines(0, 0, -1, true)[1] == "" then
@@ -150,10 +159,16 @@ local function run_problem()
 		lsp.lsp_format({ async = true })
 	end
 
-	vim.system({ "make", "run", vim.fn.expand("%:t") }, {}, function()
-		vim.schedule(function()
-			vim.cmd.checktime()
-		end)
+	if not vim.g.cp_contest then
+		log("no contest mode set", vim.log.levels.ERROR)
+		return
+	end
+
+	local contest_config = config.contests[vim.g.cp_contest]
+
+	vim.schedule(function()
+		execute.run_problem(problem_id, contest_config, false)
+		vim.cmd.checktime()
 	end)
 end
 
@@ -168,10 +183,16 @@ local function debug_problem()
 		lsp.lsp_format({ async = true })
 	end
 
-	vim.system({ "make", "debug", vim.fn.expand("%:t") }, {}, function()
-		vim.schedule(function()
-			vim.cmd.checktime()
-		end)
+	if not vim.g.cp_contest then
+		log("no contest mode set", vim.log.levels.ERROR)
+		return
+	end
+
+	local contest_config = config.contests[vim.g.cp_contest]
+
+	vim.schedule(function()
+		execute.run_problem(problem_id, contest_config, true)
+		vim.cmd.checktime()
 	end)
 end
 
@@ -202,7 +223,8 @@ local function diff_problem()
 		end
 
 		local temp_output = vim.fn.tempname()
-		vim.fn.system(("awk '/^\\[[^]]*\\]:/ {exit} {print}' %s > %s"):format(vim.fn.shellescape(output), temp_output))
+		local result = vim.system({ "awk", "/^\\[[^]]*\\]:/ {exit} {print}", output }, { text = true }):wait()
+		vim.fn.writefile(vim.split(result.stdout, "\n"), temp_output)
 
 		local session_file = vim.fn.tempname() .. ".vim"
 		vim.cmd(("silent! mksession! %s"):format(session_file))
@@ -239,7 +261,6 @@ function M.setup(user_config)
 	config = config_module.setup(user_config)
 
 	local plugin_path = get_plugin_path()
-	config.template_dir = plugin_path .. "/templates"
 	config.snippets.path = plugin_path .. "/templates/snippets"
 
 	snippets.setup(config)
diff --git a/lua/cp/scrape.lua b/lua/cp/scrape.lua
new file mode 100644
index 0000000..dd0bb79
--- /dev/null
+++ b/lua/cp/scrape.lua
@@ -0,0 +1,68 @@
+local M = {}
+
+local function get_plugin_path()
+	local plugin_path = debug.getinfo(1, "S").source:sub(2)
+	return vim.fn.fnamemodify(plugin_path, ":h:h:h")
+end
+
+local function ensure_io_directory()
+	vim.fn.mkdir("io", "p")
+end
+
+function M.scrape_problem(contest, problem_id, problem_letter)
+	ensure_io_directory()
+
+	local plugin_path = get_plugin_path()
+	local scraper_path = plugin_path .. "/templates/scrapers/" .. contest .. ".py"
+
+	local args
+	if contest == "cses" then
+		args = { "uv", "run", scraper_path, problem_id }
+	else
+		args = { "uv", "run", scraper_path, problem_id, problem_letter }
+	end
+
+	local result = vim.system(args, {
+		cwd = plugin_path,
+		text = true,
+		timeout = 30000,
+	}):wait()
+
+	if result.code ~= 0 then
+		return {
+			success = false,
+			error = "Failed to run scraper: " .. (result.stderr or "Unknown error"),
+		}
+	end
+
+	local ok, data = pcall(vim.json.decode, result.stdout)
+	if not ok then
+		return {
+			success = false,
+			error = "Failed to parse scraper output: " .. tostring(data),
+		}
+	end
+
+	if not data.success then
+		return data
+	end
+
+	local full_problem_id = data.problem_id
+	local input_file = "io/" .. full_problem_id .. ".in"
+	local expected_file = "io/" .. full_problem_id .. ".expected"
+
+	if #data.test_cases > 0 then
+		local first_test = data.test_cases[1]
+		vim.fn.writefile(vim.split(first_test.input, "\n"), input_file)
+		vim.fn.writefile(vim.split(first_test.output, "\n"), expected_file)
+	end
+
+	return {
+		success = true,
+		problem_id = full_problem_id,
+		test_count = #data.test_cases,
+		url = data.url,
+	}
+end
+
+return M
diff --git a/readme.md b/readme.md
index 15405b5..cda6d7c 100644
--- a/readme.md
+++ b/readme.md
@@ -19,8 +19,6 @@ neovim plugin for competitive programming.
 - `make`
 -  [uv](https://docs.astral.sh/uv/): problem scraping (optional)
 - [LuaSnip](https://github.com/L3MON4D3/LuaSnip): contest-specific snippets (optional)
-- [vim-zoom](https://github.com/dhruvasagar/vim-zoom): better diff view
-  (optional)
 
 ## Installation
 
diff --git a/templates/compile_flags.txt b/templates/compile_flags.txt
deleted file mode 100644
index 04b1b00..0000000
--- a/templates/compile_flags.txt
+++ /dev/null
@@ -1,2 +0,0 @@
--O2
--DLOCAL
diff --git a/templates/debug_flags.txt b/templates/debug_flags.txt
deleted file mode 100644
index a2c29c5..0000000
--- a/templates/debug_flags.txt
+++ /dev/null
@@ -1,3 +0,0 @@
--g3
--fsanitize=address,undefined
--DLOCAL
diff --git a/templates/scrapers/atcoder.py b/templates/scrapers/atcoder.py
index 374ffdb..788a573 100644
--- a/templates/scrapers/atcoder.py
+++ b/templates/scrapers/atcoder.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 
+import json
 import sys
 
 import requests
@@ -57,12 +58,17 @@ def scrape(url: str) -> list[tuple[str, str]]:
 
 def main():
     if len(sys.argv) != 3:
-        print("Usage: atcoder.py <contest_id> <problem_letter>", file=sys.stderr)
-        print("Example: atcoder.py abc042 a", file=sys.stderr)
+        result = {
+            "success": False,
+            "error": "Usage: atcoder.py <contest_id> <problem_letter>",
+            "problem_id": None,
+        }
+        print(json.dumps(result))
         sys.exit(1)
 
     contest_id = sys.argv[1]
     problem_letter = sys.argv[2]
+    problem_id = contest_id + problem_letter
 
     url = parse_problem_url(contest_id, problem_letter)
     print(f"Scraping: {url}", file=sys.stderr)
@@ -70,17 +76,27 @@ def main():
     tests = scrape(url)
 
     if not tests:
-        print(f"No tests found for {contest_id} {problem_letter}", file=sys.stderr)
+        result = {
+            "success": False,
+            "error": f"No tests found for {contest_id} {problem_letter}",
+            "problem_id": problem_id,
+            "url": url,
+        }
+        print(json.dumps(result))
         sys.exit(1)
 
-    print("---INPUT---")
-    print(len(tests))
+    test_cases = []
     for input_data, output_data in tests:
-        print(input_data)
-    print("---OUTPUT---")
-    for input_data, output_data in tests:
-        print(output_data)
-    print("---END---")
+        test_cases.append({"input": input_data, "output": output_data})
+
+    result = {
+        "success": True,
+        "problem_id": problem_id,
+        "url": url,
+        "test_cases": test_cases,
+    }
+
+    print(json.dumps(result))
 
 
 if __name__ == "__main__":
diff --git a/templates/scrapers/codeforces.py b/templates/scrapers/codeforces.py
index ed31990..d1c24fa 100644
--- a/templates/scrapers/codeforces.py
+++ b/templates/scrapers/codeforces.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 
+import json
 import sys
 
 import cloudscraper
@@ -73,31 +74,43 @@ def scrape_sample_tests(url: str):
 
 def main():
     if len(sys.argv) != 3:
-        print("Usage: codeforces.py <contest_id> <problem_letter>", file=sys.stderr)
-        print("Example: codeforces.py 1234 A", file=sys.stderr)
+        result = {
+            "success": False,
+            "error": "Usage: codeforces.py <contest_id> <problem_letter>",
+            "problem_id": None,
+        }
+        print(json.dumps(result))
         sys.exit(1)
 
     contest_id = sys.argv[1]
     problem_letter = sys.argv[2]
+    problem_id = contest_id + problem_letter.upper()
 
     url = parse_problem_url(contest_id, problem_letter)
     tests = scrape_sample_tests(url)
 
     if not tests:
-        print(f"No tests found for {contest_id} {problem_letter}", file=sys.stderr)
-        print(
-            "Consider adding test cases manually to the io/ directory", file=sys.stderr
-        )
+        result = {
+            "success": False,
+            "error": f"No tests found for {contest_id} {problem_letter}",
+            "problem_id": problem_id,
+            "url": url,
+        }
+        print(json.dumps(result))
         sys.exit(1)
 
-    print("---INPUT---")
-    print(len(tests))
+    test_cases = []
     for input_data, output_data in tests:
-        print(input_data)
-    print("---OUTPUT---")
-    for input_data, output_data in tests:
-        print(output_data)
-    print("---END---")
+        test_cases.append({"input": input_data, "output": output_data})
+
+    result = {
+        "success": True,
+        "problem_id": problem_id,
+        "url": url,
+        "test_cases": test_cases,
+    }
+
+    print(json.dumps(result))
 
 
 if __name__ == "__main__":
diff --git a/templates/scrapers/cses.py b/templates/scrapers/cses.py
index 38d43aa..8da2ba6 100755
--- a/templates/scrapers/cses.py
+++ b/templates/scrapers/cses.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 
+import json
 import sys
 
 import requests
@@ -57,31 +58,54 @@ def scrape(url: str) -> list[tuple[str, str]]:
 
 def main():
     if len(sys.argv) != 2:
-        print("Usage: cses.py <problem_id_or_url>", file=sys.stderr)
+        result = {
+            "success": False,
+            "error": "Usage: cses.py <problem_id_or_url>",
+            "problem_id": None,
+        }
+        print(json.dumps(result))
         sys.exit(1)
 
     problem_input = sys.argv[1]
     url = parse_problem_url(problem_input)
 
     if not url:
-        print(f"Invalid problem input: {problem_input}", file=sys.stderr)
-        print("Use either problem ID (e.g., 1068) or full URL", file=sys.stderr)
+        result = {
+            "success": False,
+            "error": f"Invalid problem input: {problem_input}. Use either problem ID (e.g., 1068) or full URL",
+            "problem_id": problem_input if problem_input.isdigit() else None,
+        }
+        print(json.dumps(result))
         sys.exit(1)
 
     tests = scrape(url)
 
+    problem_id = (
+        problem_input if problem_input.isdigit() else problem_input.split("/")[-1]
+    )
+
     if not tests:
-        print(f"No tests found for {problem_input}", file=sys.stderr)
+        result = {
+            "success": False,
+            "error": f"No tests found for {problem_input}",
+            "problem_id": problem_id,
+            "url": url,
+        }
+        print(json.dumps(result))
         sys.exit(1)
 
-    print("---INPUT---")
-    print(len(tests))
+    test_cases = []
     for input_data, output_data in tests:
-        print(input_data)
-    print("---OUTPUT---")
-    for input_data, output_data in tests:
-        print(output_data)
-    print("---END---")
+        test_cases.append({"input": input_data, "output": output_data})
+
+    result = {
+        "success": True,
+        "problem_id": problem_id,
+        "url": url,
+        "test_cases": test_cases,
+    }
+
+    print(json.dumps(result))
 
 
 if __name__ == "__main__":