Watch the algorithm think

Algorithms you can see.

Every pattern, stepped through one frame at a time — pointers gliding, trees recursing, DP tables filling in. Press play and watch the idea unfold.

live
two‑pointers · target 14
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4
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15
L
R
1 + 15 = 16 > 14 — move right in
two‑sum · approaches
Time
O(n²)
Space
O(1)
Work to solve · n = 1,0001,000,000 ops

Check every pair — two nested loops over the array.

↑ tap an approach to leap — the cost falls as you go.
Brute force → better

Never stop at the first answer.

Every problem carries its approaches side by side — the obvious brute force and the sharp optimization. Jump between them in a tap and watch the time and space complexity fall, so you learn the why, not just the trick.

Pick a track

visualcode teaches each topic the same way — by animating it. Jump straight in.

New·Interview Prep

Prep like the interview’s next week.

Turn the whole problem library into a plan you can actually finish. Pick a timed track — 7, 30, or 45 days at 1, 2, or 4 problems a day — and get a calendar-anchored schedule spread across every topic, with a Today marker and an on-track read-out. Or take the complete track: the entire pool as one topic-grouped checklist.

interview prep · your plan
Mode
TimedComplete
Days
73045
Per day
124
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2
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5
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14
On track0 / 60 solved · 0%