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 listDec 28, 2025 19:04Josu San MartinJosu San MartinError
Source Code

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Challenge History
DateChallengerCostTypeStatus
Sep 11, 2026 14:02Andrew Epstein13.09CustomSolution Broken
Run Statistics
#DateScoreWall TimeCPU UserCPU SystemMemoryError
1Sep 11, 2026 14:03018,506,9316,630,0001,207,00098,304Exit with code 2: unexpected fault address 0x7536a4ac0 fatal error: fault [signal SIGSEGV: segmentation violation code=0x1 addr=0x7536a4ac0 pc=0x473974] goroutine 1 gp=0xc000002380 m=0 mp=0x511ae0 [running]: runtime.throw({0x488e08?, 0x0?}) /compiler...stderr
2Dec 28, 2025 19:0412,80725,217,5046,367,0001,061,0002,510,848
3Dec 28, 2025 19:0413,16026,887,5757,633,00002,494,464
4Dec 28, 2025 19:0413,22223,585,5826,574,0001,095,0002,502,656
5Dec 28, 2025 19:0413,24126,723,6077,680,00002,478,080
6Dec 28, 2025 19:0413,82124,719,7406,012,0002,004,0002,416,640
7Dec 28, 2025 19:0413,94028,692,1866,064,0002,021,0002,412,544