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 listMar 3, 2026 00:40JuneLJuneLError
Source Code

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Challenge History
DateChallengerCostTypeStatus
Oct 5, 2026 18:38Andrew Epstein10.00CustomSolution Broken
Run Statistics
#DateScoreWall TimeCPU UserCPU SystemMemoryError
1Oct 5, 2026 18:42011,069,769954,000024,576No answer to stdout. Died or killed?
2Mar 3, 2026 00:4043,75246,306,21224,361,0001,015,0002,269,184
3Mar 3, 2026 00:4044,20549,546,23924,614,0001,025,0002,396,160
4Mar 3, 2026 00:4144,29556,302,17424,664,0001,027,0002,441,216
5Mar 3, 2026 00:4144,30052,360,99124,667,0001,027,0002,465,792
6Mar 3, 2026 00:4144,38856,817,12424,716,0001,029,0002,306,048
7Mar 3, 2026 00:4044,39051,939,76225,746,00002,478,080
8Mar 3, 2026 00:4144,41258,934,43625,759,00002,514,944
9Mar 3, 2026 00:4144,65353,395,79324,903,000996,0002,412,544
10Mar 3, 2026 00:4044,67452,877,39224,915,000996,0002,338,816
11Mar 3, 2026 00:4044,67653,086,20223,919,0001,993,0002,523,136
12Mar 3, 2026 00:4044,71751,793,92423,941,0001,995,0002,416,640
13Mar 3, 2026 00:4144,72854,316,72425,942,00002,457,600
14Mar 3, 2026 00:4144,87257,912,08624,024,0002,002,0002,428,928
15Mar 3, 2026 00:4144,87254,621,16125,025,0001,001,0002,310,144
16Mar 3, 2026 00:4044,91751,505,45825,050,0001,002,0002,490,368
17Mar 3, 2026 00:4044,94056,061,08724,060,0002,005,0002,514,944
18Mar 3, 2026 00:4044,97856,463,28824,081,0002,006,0002,437,120
19Mar 3, 2026 00:4145,17948,639,73925,197,0001,007,0002,502,656