7 difficulty tiers × 100 problems — exam-style C practice
Practice C the way the exam actually asks.
Free online judge for C programming — 700 exam-style and contest problems, organized from Very Easy to Extreme. Write in the browser, run custom input, then submit against hidden tests for a real AC / WA / TLE verdict.
Run without an account · Sign in to submit and enter contests
#include <stdio.h> int main(void) { long long n, sum = 0; scanf("%lld", &n); for (long long i = 1; i <= n; i++) sum += i; printf("%lld\n", sum); return 0;}- Sample #14 msAC
- Hidden #26 msAC
- Hidden #3 · n = 10⁹11 msAC
- C problems
- 700
- Difficulty tiers
- 7
- Institutions
- 60
- Practice access
- 24/7
Why it holds up
Built like a real judge, not a quiz app.
Verdicts in milliseconds
Every submission is compiled with gcc/clang and run against hidden tests with real time limits. You get AC, WA, TLE, RE, or the exact compiler error — never a vague pass/fail.
Practice by difficulty
Browse 700 problems across seven clear difficulty tiers, from first C programs through Extreme contest-level challenges.
Contests run by your faculty
Admins schedule contests, pick the problem order, set the window and penalty rules, then flip them live. Standings update as submissions land.
Progress that survives
Write and run code without an account. Sign in when you are ready to submit — every accepted answer, submission, and contest result is stored against your university profile.
The loop
Three keystrokes from idea to verdict.
⌘/Ctrl + Enter submits without leaving the editor.
- 01
Open a problem
Statement, constraints, and samples sit beside the editor — no tab juggling.
- 02
Run your own input
Test against custom stdin before it counts. Drafts autosave in your browser.
- 03
Submit for the verdict
Hidden tests, per-test timing, and a diff of expected against what you printed.
Contests
Four campuses, one scoreboard.
CodeHub contests are configured end to end by administrators: problem order, start and end time, penalty per wrong submission, and who is allowed to register. When a contest goes live, standings rank by problems solved, then by penalty — the same rules you will meet at the take-off contest.
Institution directory
60+ Bangladeshi institutions, each with its own standings.
DIU
RankedBUET
RankedDU
RankedNSU
RankedCUET
Ranked
FAQ
Online C judge, answered quickly.
- What is CodeHub?
- CodeHub is a free online judge for C programming from Daffodil International University. It offers 700 exam-style C practice problems, instant gcc/clang judging, and live inter-university contests for DIU, NSU, AIUB, and BRAC.
- Do I need an account to practice C problems?
- No. You can open any problem, write C in the browser, and run custom input without signing in. Create an account when you want to submit for an official verdict, save progress, or join contests.
- Which programming language does the judge support?
- C only. Submissions are compiled with gcc/clang and graded against hidden tests with real time limits, returning AC, WA, TLE, RE, MLE, or CE.
- Who can join the contests?
- Students from Daffodil International University, North South University, AIUB, and BRAC University can register for live contests when an admin activates them. Contests use ICPC-style scoring with penalty for wrong submissions.
- Is CodeHub free?
- Yes. The problem bank, online C compiler/judge, and practice leaderboards are free. Contests are also free when faculty or admins run them.
The next contest is graded the same way this page is.
Create an account with your university, keep every accepted solution, and show up on the board.