Order book Yuriy Lyfenko

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.

Back to listFeb 8, 2026 13:14Daniel MastalerzDaniel MastalerzError
Source Code

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Challenge History
DateChallengerCostTypeStatus
Oct 5, 2026 19:29Andrew Epstein10.00CustomSolution Broken
Run Statistics
#DateScoreWall TimeCPU UserCPU SystemMemoryError
1Oct 5, 2026 19:38010,912,663743,000024,576No answer to stdout. Died or killed?stderr
2Feb 8, 2026 13:14107,60392,740,44862,410,00002,273,280
3Feb 8, 2026 13:14107,77287,980,35662,508,00002,510,848
4Feb 8, 2026 13:14107,99389,487,27261,626,0001,010,0002,387,968
5Feb 8, 2026 13:14108,53488,221,21960,952,0001,998,0002,273,280
6Feb 8, 2026 13:14108,61085,682,82460,995,0001,999,0002,392,064
7Feb 8, 2026 13:14110,30387,632,85462,977,000999,0002,510,848
8Feb 8, 2026 13:14110,41487,060,14862,039,0002,001,0002,400,256
9Feb 8, 2026 13:14110,67686,759,05963,189,0001,003,0002,404,352
10Feb 8, 2026 13:14110,69784,899,29663,201,0001,003,0002,273,280