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CF Expert but bombed my first real interview. interviewer said 'communication'. what does that even mean for a coding round?

Mahin Hasan@mahin_cp

September 15, 2026 · 1 min read

ok so. codeforces expert (1680), ICPC regionals twice. first internship interview yesterday, dhaka product company, panel was remote from singapore.

problem was a medium graph thing. had the idea in 2 min, coded it in 8, passed all their cases. feedback today: "strong problem solving, weak communication, no hire."

bro WHAT. i solved it. faster than anyone they've probably seen. what do they want, a ted talk?

also this was at the top of my code, if that matters:

#define ll long long
#define pb push_back
#define all(x) (x).begin(), (x).end()
// interviewer apparently did not love this 💀

genuinely asking: how do i fix this when my brain finishes the solution before i can explain it?

Accepted answer

Kunal Bhatia#2 in Interview Horror Stories8 likes

Mahin, I'll be honest because I know you can take it. On Codeforces, a judge reads your code. In an interview, a human is scoring HOW you got there, because on the job your teammates have to follow your reasoning in design docs and code reviews. What "communication" means concretely on their rubric: 1. Restate the problem and ask 1-2 clarifying questions (directed? weighted? can it be disconnected?), even if you already know. 2. Say the brute force in one sentence, and why it's too slow. 3. Say the idea before coding: "multi-source BFS, because...". 4. Narrate lightly while coding. Not a TED talk, just signposts. 5. Dry run a small example before saying "done". Give the complexity without being asked. 6. Readable names, no macros. You're writing for a reader now, not a judge. Your speed is a huge asset. Slow down to 70% and spend the saved time on 1, 2, 3 and 5. You'll be a strong hire everywhere. And yes, I'm still saying LeetCode-style interviews are their own skill 😄 You can be much better than me at CF and still need this.

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Rafiul Islam@rafi_dhaka#10 in Interview Horror Stories
vai the #define all(x) in an interview 😂 I love you but no
6 net votes
Mahin Hasan@mahin_cp#5 in Interview Horror Stories
it saves 10 seconds!!
1 net votes
Rafiul Islam@rafi_dhaka#10 in Interview Horror Stories
and costs one offer. great trade
0 net votes

Accepted answer

Kunal Bhatia@kunal_dsa#2 in Interview Horror Stories
Mahin, I'll be honest because I know you can take it. On Codeforces, a judge reads your code. In an interview, a human is scoring HOW you got there, because on the job your teammates have to follow your reasoning in design docs and code reviews. What "communication" means concretely on their rubric: 1. Restate the problem and ask 1-2 clarifying questions (directed? weighted? can it be disconnected?), even if you already know. 2. Say the brute force in one sentence, and why it's too slow. 3. Say the idea before coding: "multi-source BFS, because...". 4. Narrate lightly while coding. Not a TED talk, just signposts. 5. Dry run a small example before saying "done". Give the complexity without being asked. 6. Readable names, no macros. You're writing for a reader now, not a judge. Your speed is a huge asset. Slow down to 70% and spend the saved time on 1, 2, 3 and 5. You'll be a strong hire everywhere. And yes, I'm still saying LeetCode-style interviews are their own skill 😄 You can be much better than me at CF and still need this.
8 net votes
Mahin Hasan@mahin_cp#5 in Interview Horror Stories
ok this is... annoyingly correct. 70% speed + talk. trying it in the next one. you win this round kunal vai
1 net votes
Kunal Bhatia@kunal_dsa#2 in Interview Horror Stories
Writing down today's date. The day I won an argument with Mahin.
2 net votes
Ankit Khurana@faang_or_bust#9 in Interview Horror Stories
solving in 8 min and getting no hire is a skill issue. communication is part of the job. basic stuff btw
2 net votes
Nikhil Sharan@nikhil_twopointers#1 in Interview Horror Stories
Very common with strong CP folks. You think in jumps, interviewers grade steps. Practise by recording yourself solving one problem a day out loud, 10 minutes. Painful to watch, very effective.
6 net votes
Renee Whitfield@renee_em6 rep in Interview Horror Stories
From the hiring side: we're also asking ourselves "would I enjoy working on a hard bug with this person?" You clearly have the speed. Let them into your head and you'll be very hireable.
0 net votes
Tahmina Akter@tahmina_qa1 rep in Interview Horror Stories
From Dhaka also 🙏 good that you posted this, many CP people at our university have the same problem
1 net votes
Mahin Hasan@mahin_cp#5 in Interview Horror Stories
update: had another interview today. talked like a podcast host. moved to the next round 😤🔥
1 net votes