diff --git a/lua/cp/init.lua b/lua/cp/init.lua
index 893a50f..6f49f81 100644
--- a/lua/cp/init.lua
+++ b/lua/cp/init.lua
@@ -23,16 +23,14 @@ local state = {
 	platform = nil,
 	contest_id = nil,
 	problem_id = nil,
-	diff_mode = false,
 	saved_layout = nil,
 	saved_session = nil,
-	temp_output = nil,
 	test_cases = nil,
 	test_states = {},
 }
 
 local platforms = { "atcoder", "codeforces", "cses" }
-local actions = { "run", "debug", "diff", "next", "prev" }
+local actions = { "run", "debug", "next", "prev" }
 
 local function set_platform(platform)
 	if not vim.tbl_contains(platforms, platform) then
@@ -66,19 +64,6 @@ local function setup_problem(contest_id, problem_id, language)
 		)
 	end
 
-	if state.diff_mode then
-		vim.cmd.diffoff()
-		if state.saved_session then
-			vim.fn.delete(state.saved_session)
-			state.saved_session = nil
-		end
-		if state.temp_output then
-			vim.fn.delete(state.temp_output)
-			state.temp_output = nil
-		end
-		state.diff_mode = false
-	end
-
 	vim.cmd("silent only")
 
 	state.contest_id = contest_id
diff --git a/plugin/cp.lua b/plugin/cp.lua
index 9e19695..ee9e817 100644
--- a/plugin/cp.lua
+++ b/plugin/cp.lua
@@ -4,7 +4,7 @@ end
 vim.g.loaded_cp = 1
 
 local platforms = { "atcoder", "codeforces", "cses" }
-local actions = { "run", "debug", "diff", "next", "prev" }
+local actions = { "run", "debug", "next", "prev" }
 
 vim.api.nvim_create_user_command("CP", function(opts)
 	local cp = require("cp")
diff --git a/readme.md b/readme.md
index 0cf652f..bbec5a4 100644
--- a/readme.md
+++ b/readme.md
@@ -62,6 +62,7 @@ follows:
 ## Similar Projects
 
 - [competitest.nvim](https://github.com/xeluxee/competitest.nvim)
+- [assistant.nvim](https://github.com/A7Lavinraj/assistant.nvim)
 
 ## TODO
 
@@ -70,3 +71,5 @@ follows:
 - test case management
 - USACO support
 - new video with functionality, notify discord members
+- note that codeforces support is scuffed: https://codeforces.com/blog/entry/146423
+- codeforces: use round number & api not the contest id