I could solve it at my desk. I froze the second someone watched.

The first time I bombed a coding round I wasn't stuck on the algorithm. I'd done the two-pointer pattern maybe 30 times that month. What got me was the silence after "walk me through your approach," and a stranger watching me think.
If you've done this, you know the thing nobody says: the coding round mostly isn't a test of whether you can code. You can clearly code, you do it every day. It's a test of whether you can keep thinking in a structured way while observed, on a clock. That's a different skill, and almost no one practices it directly.
So when you grind another 40 LeetCode problems alone in a quiet room, you're training the part you're already fine at, and skipping the part that's failing you. Interviewers are reading whether you restate the problem, say your assumptions out loud, and talk through a wall instead of going silent. None of that shows up when you practice by yourself.
Here's the part I'm less sure about, so take it as opinion. The biggest-payoff change for most mid-level engineers isn't a new pattern list. It's getting 6 or 7 reps of talking through code while a thing watches and scores you, before the real thing does.
The reason I build around this is boring and personal: I kept watching strong engineers, including me, lose rounds we should have won, for reasons that had nothing to do with skill. That's the gap LastRound AI is aimed at. During a real screen-share it surfaces a structured approach on your screen, invisible on the share, so you don't stall at "where do I even start." And the 177 step-through explainers (HTTPS, load balancing, two-pointer, RAG) let you see the system move before you have to whiteboard it.
You don't need the tool to start, though. Tonight: pick one problem, set a 25-minute timer, solve it out loud, record yourself, then watch it back with the sound on. It's uncomfortable, which is the point. Three rounds over a week and the room stops being novel.
So, the question I wish someone asked me before my 11th interview: when did you last solve a problem out loud, on a timer, while something watched, and then watch yourself do it? If the answer is never, that's not a coding gap.
The live assistant and the explainers are free to start at lastroundai.com.