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 21, 2025 19:04Josu San MartinJosu San MartinError
Source Code

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Challenge History
DateChallengerCostTypeStatus
Sep 15, 2026 12:26Andrew Epstein10.00CustomSolution Broken
Run Statistics
#DateScoreWall TimeCPU UserCPU SystemMemoryError
1Sep 15, 2026 12:35011,273,581785,000020,480No answer to stdout. Died or killed?
2Dec 21, 2025 19:0435,62849,148,78719,631,0001,033,0002,453,504
3Dec 21, 2025 19:0735,82945,284,87220,781,00002,465,792
4Dec 21, 2025 19:0436,02949,269,65417,912,0002,985,0002,490,368
5Dec 21, 2025 19:0436,04355,499,42419,910,000995,0002,506,752
6Dec 21, 2025 19:0736,10343,966,45819,893,0001,047,0002,490,368
7Dec 21, 2025 19:0436,13449,630,99119,960,000998,0002,408,448
8Dec 22, 2025 01:4636,31453,361,86821,062,00002,424,832
9Dec 21, 2025 19:0436,31752,402,86419,058,0002,006,0002,465,792
10Dec 21, 2025 19:0436,71041,101,45220,279,0001,013,0002,387,968
11Dec 21, 2025 19:0736,73445,049,93520,292,0001,014,0002,465,792
12Dec 21, 2025 19:0436,77244,326,06721,328,00002,342,912
13Dec 22, 2025 01:4636,95349,232,04320,413,0001,020,0002,322,432
14Dec 21, 2025 19:0436,97443,638,34720,424,0001,021,0002,478,080
15Dec 21, 2025 19:0437,05741,919,15421,493,00002,363,392
16Dec 21, 2025 19:0437,08644,263,74220,486,0001,024,0002,473,984
17Dec 21, 2025 19:0437,12844,505,37721,534,00002,293,760
18Dec 21, 2025 19:0437,20242,381,67520,550,0001,027,0002,269,184
19Dec 22, 2025 01:4637,40553,144,20020,662,0001,033,0002,326,528