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 19, 2026 10:47Dominique GarmierDominique GarmierError
Source Code

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Challenge History
DateChallengerCostTypeStatus
Sep 11, 2026 16:04Andrew Epstein10.00CustomSolution Broken
Run Statistics
#DateScoreWall TimeCPU UserCPU SystemMemoryError
1Sep 11, 2026 16:10024,982,22810,538,0004,123,0002,121,728expected "869715013 ", got "0 "
2Sep 11, 2026 16:10025,205,94810,508,0004,388,0002,113,536expected "876718131 ", got "0 "
3Sep 11, 2026 16:10024,796,98810,353,0004,211,0002,113,536expected "860949166 ", got "0 "
4Mar 19, 2026 10:4717,61429,016,1149,195,0001,021,0002,519,040
5Mar 26, 2026 13:1317,69826,960,9009,239,0001,026,0002,289,664
6Mar 23, 2026 16:1217,72428,221,8748,224,0002,056,0002,293,760
7Mar 23, 2026 16:1217,88127,753,8379,334,0001,037,0002,289,664
8Mar 26, 2026 13:1317,88428,158,2289,336,0001,037,0002,293,760
9Mar 26, 2026 13:1317,89329,255,3309,341,0001,037,0002,490,368
10Mar 21, 2026 03:5417,91033,008,00310,388,00002,289,664
11Mar 23, 2026 16:1218,01228,968,1459,403,0001,044,0002,289,664
12Mar 21, 2026 03:5418,05532,365,0969,425,0001,047,0002,498,560
13Mar 21, 2026 03:5418,10727,827,8359,452,0001,050,0002,510,848
14Mar 19, 2026 10:4718,32926,503,7709,568,0001,063,0002,502,656
15Mar 19, 2026 10:4718,36728,690,2459,588,0001,065,0002,502,656