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 7, 2025 19:23Daniel HarrisDaniel HarrisError
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Run Statistics
#DateScoreWall TimeCPU UserCPU SystemMemoryError
1Feb 7, 2025 19:2200000Error: Exit with code 101: thread 'main' panicked at main.rs:78:9: index out of bounds: the len is 4096 but the index is 4099 note: run with `RUST_BACKTRACE=1` environment variable to display a backtracestderr
2Feb 7, 2025 19:2200000Error: Exit with code 101: thread 'main' panicked at main.rs:78:9: index out of bounds: the len is 4096 but the index is 4109 note: run with `RUST_BACKTRACE=1` environment variable to display a backtracestderr
3Feb 7, 2025 19:2391,63683,905,41448,135,0005,014,0002,355,200
4Feb 7, 2025 19:2392,26680,296,05948,466,0005,048,0002,510,848
5Feb 7, 2025 19:2393,73178,371,74049,331,0005,033,0002,510,848
6Feb 7, 2025 19:23119,85990,444,40165,488,0004,030,0002,523,136
7Feb 7, 2025 19:23124,50397,160,86968,201,0004,011,0002,514,944
8Feb 7, 2025 19:23128,055106,480,67171,261,0003,011,0002,347,008