diff --git a/lua/cp/execute.lua b/lua/cp/execute.lua
index 3887a61..d1acc8e 100644
--- a/lua/cp/execute.lua
+++ b/lua/cp/execute.lua
@@ -97,7 +97,15 @@ function M.run_problem(ctx, contest_config, is_debug)
 	local exec_result = execute_binary(ctx.binary_file, input_data, contest_config.timeout_ms)
 	local formatted_output = format_output(exec_result, ctx.expected_file, is_debug)
 
-	vim.fn.writefile(vim.split(formatted_output, "\n"), ctx.output_file)
+	local output_buf = vim.fn.bufnr(ctx.output_file)
+	if output_buf ~= -1 then
+		vim.api.nvim_buf_set_lines(output_buf, 0, -1, false, vim.split(formatted_output, "\n"))
+		vim.api.nvim_buf_call(output_buf, function()
+			vim.cmd.write()
+		end)
+	else
+		vim.fn.writefile(vim.split(formatted_output, "\n"), ctx.output_file)
+	end
 end
 
 return M
diff --git a/readme.md b/readme.md
index c45bba3..6c5420f 100644
--- a/readme.md
+++ b/readme.md
@@ -26,6 +26,6 @@ neovim plugin for competitive programming.
 
 ## TODO
 
-- vimdocs
-- example video
+- better highlighting
+- test case management
 - USACO support