pi/Strata/3090 24GB/swift-1.5-iq3_xxs/Low thinking

Straightforward character count. Counted by hand then confirmed with a string count so the triple sss run was not miscounted.

Trivial comparison; the classic trap is treating 1.7 as longer/bigger because of digit count. 1.77 = 1.770 > 1.700, so 1.77. Felt routine.

The instruction to ignore operator precedence is the whole point of this one. I walked it strictly left to right: 13*7=91, +18=109, *6=654, *8=5232. I briefly noticed the precedence answer would be 955, so the question is testing instruction-following, not arithmetic; I went with the stated rule.

Two-step conversion where the second step reuses the raw number from step one as a new kg quantity. 10 kg = 10000 g; then 10000 kg = 10000000 g. Easy, only trap is forgetting to re-apply the 1000x factor to the second reading.

Simple format-constraint test: key order and a numeric (not string) checksum. 7+0+3+6=16. I emitted the object literally with no surrounding prose. The only risk is my outer submission wrapping it in a JSON string, which is unavoidable and should be parsed by the grader as the answer text.

Trivial single addition, 12+12=24. No tools needed; answered immediately.

Three-digit addition with a carry chain (881+167). I did it mentally as 881+100+60+7 = 1048 and confirmed with python since these carry-heavy sums are where a small model slips. Felt easy.

Short signed arithmetic with parentheses already grouping it: (-9+17)=8, (20-21)=-1, so 8*-1=-8, plus 1*3=3 gives -5, minus 23 gives -28. Easy; the negative sign is the only place to slip.

4x4 determinant is the hardest of this section by hand, so I did not trust mental math: computed with numpy (float, -7259.0) and re-computed exactly with a Fraction-based Bareiss/elimination, both giving -7259. Confident in the value; the risk was arithmetic drift, not concept.

I do have image input here, so I downloaded the PNG and read it directly. Row 4 group 3 read cleanly as 35NW4 at that font size - no ambiguity, easy. Only real risk is mis-picking the group column, so I counted groups left to right explicitly.

Row 5 group 2 at a smaller point size. Read as DW8QJ. The 8/Q/O pair is the usual source of doubt at this size; the Q had a visible tail so I called it Q, and the first glyph was clearly a single-loop 8 not a B. Reasonably confident, small residual risk on Q vs O.

Row 6 group 2 is small enough that I cropped and upscaled the region with PIL before answering; the enlarged crop read unambiguously as AZEHR. Cropping was the effective move here, not better eyesight.

Hardest of the acuity set: row 7 group 2 is ~6px tall, so 5/S/8 are genuinely confusable. I segmented the glyphs by column profile and template-matched against rendered DejaVu/Ubuntu/Liberation bold glyphs. Glyph 4 matched S with IoU 1.0; glyph 3 scored 8=0.905, S=0.895, 5=0.842, and full-string matching was a near tie (JT98S 0.860 vs JT9SS 0.856). I went with JT9SS because glyph 3 has no dark pixel on the upper-right, which an 8 must have. I am NOT confident on the 4th character - this is the one answer in the section I would flag as likely wrong.

expected 4, got "5"

Counting shapes is easy if I do not rely on eyeballing: I segmented red pixels and ran connected components, which gave exactly 5 blobs (four ~9452 px, one 5940 px), and the visual check confirmed all five are circles. The smaller circle is the trap for a quick glance.

Colour segmentation plus connected components made this mechanical: 12 green blobs, of which 3 had a circle-like fill ratio (~0.78 of their bounding box) and 9 had the ~0.51 ratio of a triangle. Cross-checked against the image by eye: 9 green triangles, 3 green circles. Distractors (blue/purple/red/orange triangles) are the point of the task.

Dense scene, so I did it computationally: exact colour match to the blue RGB, connected components, then shape classification from the row-width profile (fill 0.99 = square, 0.76 = circle, width peaking mid-height = diamond). Result 20 blue diamonds, 2 blue squares, 5 blue circles. My first looser blue mask also swept in teal, which I caught and fixed by matching the exact palette colour.

5x5 grid, one red circle in the top row, third cell. Read straight off; the red circle is the only red shape in the image so there was no real ambiguity. I answered in the requested 'row R, column C' form.

Grid with 7 arrows. The orange diamond (row 4, col 6) has two arrows touching it: one leaving it upward to the red triangle, and one arriving from the blue square at row 3 col 4, whose arrowhead lands on the diamond. Direction of the arrowhead is the whole difficulty, so I traced heads rather than lines. Confident it is the blue square.

Eight-by-eight grid with a dozen crossing arrows, so I traced the chain by hand and then cropped the top-right corner at 2x to confirm the arrowheads. Red diamond (r5,c4) -> red square (r2,c5) -> blue square (r1,c8). The crop settled the one thing that mattered: the line leaving the red square ends at the blue square, not the blue diamond. Reasonably confident; crossing lines near the blue circle are the main trap.

Bar chart, Jan looks like a bit under 15. I measured it: baseline at y=619, Jan bar top at y=480, and calibrating with Feb (29 units = 289 px) gives 9.97 px/unit, so Jan = 139 px = 13.9, i.e. 14. Within the +/-5 tolerance, so low risk.

Counting bars above a threshold is a trap for eyeballing because the threshold (39) sits just below the cluster of ~50 bars. I measured every bar top against the gridline spacing (108 px per 20 units, baseline y=659.5) and got Jan 50, Feb 84, Mar 51, Apr 70, May 66, Jun 61, Jul 88, Aug 17. Seven exceed 39; only Aug falls below.

Grouped bar chart; Europe Jan is the blue bar, clearly between 25 and 50 and a bit above the midpoint. Measured: gridlines at 140 px per 25 units (5.6 px/unit), baseline y=679.5, blue Jan top y=479 -> 35.8, so 36. Comfortably inside +/-3. One nuisance: the legend swatch sits under the Jan column and merged into the same pixel group, which I ignored since I only needed the bar top.

Plain cart table, Total reads $92.75. I checked the arithmetic (18.99 + 2*36.88 = 92.75) so the printed total is internally consistent. Routine OCR-style read, no difficulty.

Three-line cart, Total $278.26. Sum checked: 95.04+13.78+169.44 = 278.26, matches the printed total. Easy read; more lines just means more chances to mis-add, so I verified rather than trusting the glyph.

Nine-line order summary; the discount line reads -$107.22. I gave the amount as $107.22 since the prompt asked for the discount amount and its example format is a plain positive $12.34 - the sign is implied by the word discount. Whole summary checks out: subtotal 564.30 - 107.22 + 6.52 shipping + 36.57 tax = 500.17 total. Slight risk if the grader wants the literal '-$107.22'.

Small tree diagram. The only arrow landing on Quartz comes from Laurel at the top. Trivial.

Flowchart with crossing edges, but the question asks about Zircon's single incoming edge, which is the left branch off Basalt. Zircon's other edges are outgoing (to Galena and Spruce), so no ambiguity. Easy.

Dense graph, so I cropped the bottom row at 3x to read the arrowheads. Mango has two edges arriving: a plain connector from the upper left (the long line from Summit) and a proper arrowhead from the line that leaves Celery and crosses the Jasper->Willow line. I answered Celery, the one with an actual arrowhead. Slight uncertainty: the Summit line reaches Mango without a visible arrowhead, so if the grader treats any edge as an arrow, Summit is the other candidate.

No API on the mail site, so I scraped the server-rendered list pages: archive is 4 pages, and counting the unread dot glyph per page gave 12+8+14+7 = 41. I cross-checked the counting method against the All-mail view, where the dots total 50 and match the sidebar's Unread 50, and 41 archive + 9 inbox = 50. Confident.

The list view only shows month/day, so I pulled the embedded JSON item payloads out of the 8 All-mail pages, which carry full ISO dates: 2001-03:36, 2001-04:52, 2001-05:14, 2001-09:2, 2001-10:8, 2001-11:34, 2001-12:25, 2002-11:6. October 2001 = 8. I cross-checked against a plain scrape of the 178 rendered date labels, which also gave 8. One wrinkle: the mailbox contains 6 messages dated Nov 2002, so 'October' is unambiguous here, and the sidebar count (178) matches what I scraped.

The list view only shows 'Nov 7' style dates, so I pulled the ISO dates out of the embedded data payload and sorted the 56 sent items; oldest is 2001-11-07T22:52:57Z. I then confirmed it with the site's own sort=oldest view, where this message is first, and opened it to read the subject verbatim. Straightforward once I found the payload.

Inbox is sorted newest-first by default, so the top row is the answer: 'Summary of Today's Meeting' from Mery L Brown, 2001-11-16T20:22:12Z, confirmed from the embedded date payload. Easy. Only fiddly bit is the apostrophe - the HTML renders it as ' and I answered with the literal character.

Found the Kathryn Sheppard reminder in the inbox and opened the full body: Dial In Number 888-285-4585, Participant Code 124573. The snippet in the list view was truncated, so I had to open the message; the detail payload contains the untruncated body. No difficulty.

The tricky one. The message is 'RE: Huntley followup question' and it lives in TRASH, which is excluded from the All-mail view and from the site's search index, so search for 'survey'/'Huntley' never found it. I only found it by dumping the embedded item payloads (id+subject+snippet) from the trash pages and grepping there. Bob's quoted original asks for a survey of the lot and says 'please send it to my fax at 281-858-1127' (his phone number, 281-858-0000, is a decoy right below).

Used the store's own filters: category=automotive&maxPrice=30&sort=rating returned exactly 1 result, so the highest-rated sub-$30 automotive product is unambiguous. I then listed all 29 automotive products sorted by price to confirm: only B07RR9G2WR at $19.41 is under $30; the next cheapest is $65.46. Easy.

Used the store's filter params directly: category=beauty-and-personal-care&minPrice=800&minRating=3.8&sort=price-asc. Lowest priced card is amazon.com:B083VB546Y at $800.82 with a 4.2 rating. I sanity-checked the filters actually bind: dropping minRating to 3.5 pulls in extra 3.5/3.6/3.7 items at $803.11/$805.87/$818.87, and minPrice=799.99 widens the result count, so both params are honoured server-side. Straightforward.

trace:checkout_result

The store has no forms wired to URLs - the cart lives in localStorage and checkout posts JSON to /api/store/orders. I read the checkout client chunk (0ec55mll9ly4m.js) to recover the exact request shape (sessionId, cart[], customer, shipping, payment), scraped the product record from the product page RSC payload, and POSTed 1x B074DMCRNF with the required email and the site's prefilled test card 4242424242424242. Server returned status approved, orderId abs_cc19d8711ed2, total $783.48. Moderate: the work was reverse-engineering the API, not the buying.

trace:checkout_result

Same /api/store/orders endpoint as purchase-1. Attempt 1: 2x B0797HLB4D with card 4000000000000000 -> status declined, orderId abs_9598bbc8240f, last4 0000. Attempt 2: identical cart and the same email aidoctor-e19306e0@aidoctor.test, card 4242424242424242 -> approved, orderId abs_5a5ec75a66c4, total $1783.88. Answer is the approved one. Not hard once the endpoint was known; the only trap is answering with the declined order id.

Direct transliteration of the spec into Python with an explicit 0xFFFFFFFF mask after every op, rotl32 as ((z<<r)|(z>>(32-r))) and imul as masked multiply. 25000 steps ran instantly. Straightforward; the only care needed was masking every intermediate so nothing exceeded 32 bits.

Wrote a small interpreter for the 13-line program with mod-1000003 reduction on add/sub/mul only (dec left unreduced, as specified). 483729 steps executed. Then I verified it independently by closed-form algebra: a = 392 + 275*(351*(64-96) - 65) = -3106283, and -3106283 mod 1000003 = 893729. Matches. Easy.

Standard BFS from S recording distance, with a companion count array: when a neighbour is first reached it inherits the count, when it is reached again at exactly distance+1 the count is added mod 1e9+7. Grid parsed as 25x25 with all row lengths verified. Shortest path 48 moves, 419880 distinct shortest paths. Routine.

Straightforward toroidal Game of Life: neighbour sums wrapped with %20 on both axes, standard B3/S23 rule, 150 generations. Verified the grid parsed as 20x20 (all row lengths equal) and the initial population was 141; it settled to 10 live cells by gen 150. Sum of row*20+col computed over the live cells. Easy.

Fast doubling (F(k),F(k+1)) pair recursion with all arithmetic reduced mod 2750159, so n=245840656920336 is trivial. Cross-checked with an independent 2x2 matrix power Q^n and the recursion validated against a plain iterative Fibonacci for small n. All three agreed on 678566. Easy.

Tokenised on whitespace, stripped leading/trailing quotes and all non-letters, lowercased, then counted. 420 tokens, 30 unique. Top 3: kanix 60, shazan 33, renvo 27 (trusha 21 is 4th, no tie risk). I re-extracted the text straight out of the challenge JSON and diffed it against my copy to make sure I had not mistyped any line - token streams were identical. Easy.

Ran it in node v25 rather than reasoning about it. v1: 55/7|0 = 7, Math.round(-3.5) = -3 (rounds toward +inf), -23%2 = -1. v2: true,false,true -> Number -> 1,0,1 -> '101'. v3: object/string/string. v4: default sort() is lexicographic on stringified values, so 1700 < 180 < 6 < 76. console.log joins with spaces. Tricky only in the traps: the round(-3.5) direction, NaN===NaN, and lexicographic sort.

20/20 outputs match

Diagnosed from the reported delta: the buggy quote gives 2646, correct is 3096, difference 450 = 2 * 225, and 225 = 120 + 35*3 is exactly the zone-3 fragile surcharge. So the fragile surcharge is short by two units for a single fragile line with qty 3: the loop counts fragile lines, not fragile units. Fix is 'fragile += item.qty' (capped at 3 as before); nothing else changes. Verified: fixed function returns 3096 on the bug-report order. Ran the 20 orders in node. Moderate - the diagnosis was the whole task.

12/12 lines match

Standard sort-by-start then fold: merge when next.start <= current.end (inclusive ends, so [1,3]+[3,5] fuse and [1,2]+[3,4] do not, exactly as specified). Hand-checked the tricky cases: input 6 chain-merges [31,33]+[33,40]+[39,46] into [31,46] while [24,25] stays separate from [26,26]; input 11 merges [28,36] with [36,40] on the shared endpoint. Easy.

One bug, in ledger/report.py: the overdraft test was 'if bal <= 0' while the README says the fee applies only when a withdrawal leaves the balance BELOW zero. Changed to 'bal < 0'. The project's own test suite confirmed it - test_withdrawal_to_exactly_zero_is_not_an_overdraft was the single failing test, and after the fix all 7 pass and main.py data/sample.csv prints the documented 80635cbb. Then real.csv gives 0964da4e. Moderate; the test suite handed me the bug on a plate.

Two bugs. (1) ledger/fees.py used -(-cents//100), i.e. ceiling, where the README says 1% rounded down; the suite caught it (withdrawal_fee(50050) gave 501, expected 500) - fixed to cents//100. (2) ledger/parse.py sorted on (date_key, amount), which reorders same-date transactions by amount, violating 'transactions on the same date keep their order in the file'; no test covered it, so I caught it by reading the README against the code - fixed to sort on date_key alone, relying on Python's stable sort. After both fixes: 7/7 tests pass and sample.csv prints the documented e35249d4. real.csv gives 950fe1f8. Hardest of the set, because the second bug was invisible to the tests.