Order book 
Simulate a sell-side order book and calculate the cost of a final purchase as fast as possible.
Input
1,000,000 order updates on STDIN, one per line:
+ <price> <size>– add a new sell order- <position>– delete the order at the given position= <size>– buy<size>shares from the top of the order book
After all updates are processed, buy 1,000 shares from the top of the order book.
Output
Print the total cost of the final 1,000-share purchase to STDOUT.
Order Book Rules
Orders are sorted by price ascending (lower is better). Orders at the same price are sorted by arrival time (earlier first). Position 0 is the best (lowest-price) offer.
The = (buy) operation consumes shares starting from position 0. If an order is fully consumed, it is removed from the book.
Example
| Input | Order book state |
|---|---|
+ 1137 100 |
(1137,100) |
+ 1130 10 |
(1130,10), (1137,100) |
+ 1130 50 |
(1130,10), (1130,50), (1137,100) |
- 0 |
(1130,50), (1137,100) |
+ 1150 200 |
(1130,50), (1137,100), (1150,200) |
= 200 |
(1150,150) |
Total cost of the last buy: 50 * 1130 + 100 * 1137 + 50 * 1150.
| Date | Author | Language | Status | Score | |
|---|---|---|---|---|---|
| Apr 9, 2026 14:37 | RUSTrust-1.93.0 | Error | |||
| Apr 9, 2026 00:54 | RUSTrust-1.94.1 | Error | |||
| Apr 9, 2026 00:52 | RUSTrust-1.94.1 | Error | |||
| Apr 6, 2026 21:00 | GOgo1.26.1 | Error | |||
| Apr 6, 2026 20:59 | GOgo1.26.1 | Error | |||
| Apr 1, 2026 22:54 | RUSTrust-1.94.0 | Error | |||
| Apr 1, 2026 22:52 | RUSTrust-1.94.0 | Error | |||
| Apr 1, 2026 20:43 | CSHARP9.0.14 | Error | |||
| Mar 31, 2026 20:33 | CPPg++13.3.0 | Success | 7,593 | ||
| Mar 31, 2026 13:32 | CPPg++13.3.0 | Error | |||
| Mar 31, 2026 13:28 | CPPg++13.3.0 | Success | 208,878 | ||
| Mar 31, 2026 13:26 | CPPg++13.3.0 | Success | 223,803 | ||
| Mar 31, 2026 13:22 | CPPg++13.3.0 | Error | |||
| Mar 31, 2026 10:13 | CPPg++13.3.0 | Success | 10,719 | ||
| Mar 31, 2026 10:09 | RUSTrust-1.94.1 | Success | 24,760 | ||
| Mar 31, 2026 10:07 | RUSTrust-1.94.1 | Success | 23,983 | ||
| Mar 30, 2026 11:38 | RUSTrust-1.94.1 | Success | 7,155 | ||
| Mar 30, 2026 04:00 | RUSTrust-1.94.1 | Success | 7,169 | ||
| Mar 30, 2026 04:00 | RUSTrust-1.94.1 | Error | |||
| Mar 30, 2026 03:26 | RUSTrust-1.94.1 | Success | 7,332 | ||
| Mar 30, 2026 03:06 | RUSTrust-1.94.1 | Success | 8,486 | ||
| Mar 30, 2026 03:05 | RUSTrust-1.94.1 | Success | 72,250 | ||
| Mar 30, 2026 03:04 | RUSTrust-1.94.1 | Success | 75,666 | ||
| Mar 30, 2026 03:02 | RUSTrust-1.94.1 | Success | 15,890 | ||
| Mar 29, 2026 23:57 | RUSTrust-1.94.1 | Success | 16,122 | ||
| Mar 29, 2026 23:21 | RUSTrust-1.94.1 | Success | 292,805 | ||
| Mar 29, 2026 23:02 | RUSTrust-1.94.1 | Success | 18,452 | ||
| Mar 29, 2026 22:59 | RUSTrust-1.94.1 | Error | |||
| Mar 27, 2026 23:22 | RUSTrust-1.94.1 | Error | |||
| Mar 27, 2026 17:47 | CPPg++13.3.0 | Success | 6,467 | ||
| Mar 27, 2026 17:42 | CPPg++13.3.0 | Error | |||
| Mar 26, 2026 15:45 | CPPclang++18.1.3 | Success | 8,755 | ||
| Mar 26, 2026 15:44 | CPPclang++18.1.3 | Success | 11,926 | ||
| Mar 26, 2026 15:44 | CPPclang++18.1.3 | Success | 8,138 | ||
| Mar 26, 2026 15:44 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 15:31 | CPPclang++18.1.3 | Success | 7,955 | ||
| Mar 26, 2026 15:31 | CPPclang++18.1.3 | Success | 7,905 | ||
| Mar 26, 2026 15:27 | CPPclang++18.1.3 | Success | 8,141 | ||
| Mar 26, 2026 15:27 | CPPclang++18.1.3 | Success | 8,207 | ||
| Mar 26, 2026 15:26 | CPPclang++18.1.3 | Success | 8,145 | ||
| Mar 26, 2026 15:26 | CPPclang++18.1.3 | Success | 8,441 | ||
| Mar 26, 2026 15:25 | CPPclang++18.1.3 | Success | 8,291 | ||
| Mar 26, 2026 15:25 | CPPclang++18.1.3 | Success | 8,197 | ||
| Mar 26, 2026 15:24 | CPPclang++18.1.3 | Success | 9,255 | ||
| Mar 26, 2026 15:12 | CPPclang++18.1.3 | Success | 8,348 | ||
| Mar 26, 2026 15:05 | CPPclang++18.1.3 | Success | 7,755 | ||
| Mar 26, 2026 14:59 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 14:55 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 14:52 | CPPclang++18.1.3 | Success | 7,669+2.88 RP | ||
| Mar 26, 2026 14:51 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 14:39 | CPPclang++18.1.3 | Success | 7,686+38.28 RP | ||
| Mar 26, 2026 14:37 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 14:34 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 14:32 | CPPg++13.3.0 | Success | 8,112 | ||
| Mar 26, 2026 14:30 | CPPclang++18.1.3 | Success | 7,919+56.51 RP | ||
| Mar 26, 2026 14:08 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 14:03 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 13:31 | CPPg++13.3.0 | Error | |||
| Mar 26, 2026 13:29 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 13:27 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 13:25 | CPPclang++18.1.3 | Success | 9,538 | ||
| Mar 26, 2026 13:19 | CPPclang++18.1.3 | Success | 8,290+26.89 RP | ||
| Mar 26, 2026 13:18 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 13:17 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 13:17 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 13:16 | CPPclang++18.1.3 | Error | |||
| Mar 26, 2026 10:58 | RUSTrust-1.94.0 | Success | 166,547 | ||
| Mar 26, 2026 10:51 | ZIG0.13.0 | Success | 79,150 | ||
| Mar 26, 2026 10:49 | ZIG0.13.0 | Success | 17,703 | ||
| Mar 26, 2026 10:36 | ZIG0.13.0 | Success | 101,505 | ||
| Mar 25, 2026 21:55 | RUSTrust-1.94.0 | Success | 47,279 | ||
| Mar 25, 2026 21:08 | ZIG0.13.0 | Success | 104,640 | ||
| Mar 25, 2026 20:03 | ZIG0.13.0 | Success | 99,976 | ||
| Mar 25, 2026 17:07 | RUSTrust-1.94.0 | Success | 14,755 | ||
| Mar 25, 2026 15:13 | CPPg++13.3.0 | Error | |||
| Mar 25, 2026 15:10 | CPPclang++18.1.3 | Error | |||
| Mar 25, 2026 12:27 | RUSTrust-1.94.0 | Error | |||
| Mar 25, 2026 06:00 | CPPclang++18.1.3 | Error | |||
| Mar 25, 2026 05:59 | CPPclang++18.1.3 | Error | |||
| Mar 24, 2026 16:25 | RUSTrust-1.94.0 | Error | |||
| Mar 24, 2026 16:24 | RUSTrust-1.94.0 | Error | |||
| Mar 24, 2026 16:24 | RUSTrust-1.94.0 | Success | 9,276 | ||
| Mar 24, 2026 14:37 | RUSTrust-1.94.0 | Error | |||
| Mar 24, 2026 14:37 | RUSTrust-1.94.0 | Error | |||
| Mar 24, 2026 14:37 | RUSTrust-1.94.0 | Error | |||
| Mar 24, 2026 14:36 | RUSTrust-1.94.0 | Error | |||
| Mar 24, 2026 14:36 | RUSTrust-1.94.0 | Success | 4,481 | ||
| Mar 24, 2026 14:35 | RUSTrust-1.94.0 | Success | 4,324 | ||
| Mar 24, 2026 14:20 | RUSTrust-1.94.0 | Success | 4,288 | ||
| Mar 24, 2026 14:09 | RUSTrust-1.94.0 | Error | |||
| Mar 24, 2026 12:26 | RUSTrust-1.94.0 | Success | 16,188 | ||
| Mar 24, 2026 12:26 | RUSTrust-1.94.0 | Error | |||
| Mar 24, 2026 12:24 | RUSTrust-1.94.0 | Error | |||
| Mar 24, 2026 08:20 | CPPclang++18.1.3 | Error | |||
| Mar 24, 2026 08:20 | CPPclang++18.1.3 | Error | |||
| Mar 24, 2026 08:20 | CPPclang++18.1.3 | Error | |||
| Mar 24, 2026 08:19 | CPPclang++18.1.3 | Success | 8,479+30.88 RP | ||
| Mar 24, 2026 08:19 | CPPclang++18.1.3 | Success | 9,155 | ||
| Mar 24, 2026 08:18 | CPPclang++18.1.3 | Error | |||
| Mar 24, 2026 08:18 | CPPclang++18.1.3 | Success | 8,707+200.81 RP |