Codeforces : https://codeforces.com/profile/Blackbeard99
Codechef : https://www.codechef.com/users/sayed_tahsin
Leetcode : https://leetcode.com/Sayed_Tahsin/
atCoder : https://atcoder.jp/users/Blackbeard
LightOj : https://lightoj.com/user/blackbeard
Uva : https://uhunt.onlinejudge.org/id/1096936
CSES : https://cses.fi/user/57363
VJudge : https://vjudge.net/user/SayedTahsin
Stopstalk : https://www.stopstalk.com/user/profile/BlackBeard561