Topic 02 — Prefix Sum
Finished Mon, Aug 24, 2026, 2:20 PM ET: all 3 core problems closed, 3 problems closed that day.
Scheduled: Tue Aug 18, 2026 · Phase: Phase I — Linear Structures · Topic: #4 · Builds on: Topic 1
Closed Aug 24 — the day the topic finished
| Issue | Problem | Set | Difficulty | Closed (ET) | Solution |
|---|---|---|---|---|---|
| #36 | LC 303 · Range Sum Query | core | easy | Aug 24 | js · docs |
| #37 | LC 238 · Product of Array Except Self | core | medium | Aug 24 | js · docs |
| #38 | LC 560 · Subarray Sum Equals K | core | medium | Aug 24 | js · docs |
Open at release
| Issue | Problem | Set | Difficulty | Closed (ET) | Solution |
|---|---|---|---|---|---|
| #39 | LC 525 · Contiguous Array | optional | medium | — | — |
| #40 | LC 974 · Subarray Sums Divisible by K | optional | medium | — | — |
20260824.182003.000000000 is timever for the UTC instant the core set completed; it tags 32a41bd, the last main commit before it.