Order book 
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.
Source Code
Source code access is restricted. Log in to request access.
Challenge History
No challenges yet.
Run Statistics
| # | Date | Score | Wall Time | CPU User | CPU System | Memory | Error | |
|---|---|---|---|---|---|---|---|---|
| 1 | Apr 15, 2025 03:27 | 0 | 0 | 0 | 0 | 0 | Error: Exit with code 101: thread 'main' panicked at fenwick.rs:91:9: index out of bounds: the len is 950 but the index is 18446744073709551604 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace | stderr |
| 2 | Apr 15, 2025 03:29 | 0 | 0 | 0 | 0 | 0 | Error: Killed by timeout | |
| 3 | Apr 15, 2025 03:29 | 0 | 0 | 0 | 0 | 0 | Error: Exit with code 101: thread 'main' panicked at fenwick.rs:91:9: index out of bounds: the len is 950 but the index is 18446744073709551612 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace | stderr |
| 4 | Apr 15, 2025 03:29 | 0 | 0 | 0 | 0 | 0 | Error: expected "2436653 ", got "0 " | |
| 5 | Apr 15, 2025 03:29 | 0 | 0 | 0 | 0 | 0 | Error: Exit with code 101: thread 'main' panicked at fenwick.rs:91:9: index out of bounds: the len is 950 but the index is 18446744073709551609 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace | stderr |
| 6 | Apr 15, 2025 03:29 | 0 | 0 | 0 | 0 | 0 | Error: expected "1433969 ", got "0 " | |
| 7 | Apr 15, 2025 03:29 | 0 | 0 | 0 | 0 | 0 | Error: expected "2014588 ", got "0 " | |
| 8 | Apr 15, 2025 03:28 | 0 | 0 | 0 | 0 | 0 | Error: expected "1677000 ", got "0 " | |
| 9 | Apr 15, 2025 03:28 | 0 | 0 | 0 | 0 | 0 | Error: expected "2050384 ", got "0 " | |
| 10 | Apr 15, 2025 03:28 | 0 | 0 | 0 | 0 | 0 | Error: expected "1250070 ", got "164868 " | |
| 11 | Apr 15, 2025 03:28 | 0 | 0 | 0 | 0 | 0 | Error: Exit with code 101: thread 'main' panicked at fenwick.rs:91:9: index out of bounds: the len is 950 but the index is 18446744073709551609 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace | stderr |
| 12 | Apr 15, 2025 03:27 | 0 | 0 | 0 | 0 | 0 | Error: Exit with code 101: thread 'main' panicked at fenwick.rs:91:9: index out of bounds: the len is 950 but the index is 18446744073709551584 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace | stderr |
| 13 | Apr 15, 2025 03:24 | 0 | 0 | 0 | 0 | 0 | Error: Exit with code 101: thread 'main' panicked at fenwick.rs:91:9: index out of bounds: the len is 950 but the index is 18446744073709551613 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace | stderr |
| 14 | Apr 15, 2025 03:27 | 0 | 0 | 0 | 0 | 0 | Error: Exit with code 101: thread 'main' panicked at fenwick.rs:91:9: index out of bounds: the len is 950 but the index is 18446744073709551602 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace | stderr |
| 15 | Apr 15, 2025 03:27 | 0 | 0 | 0 | 0 | 0 | Error: expected "1843931 ", got "0 " | |
| 16 | Apr 15, 2025 03:27 | 0 | 0 | 0 | 0 | 0 | Error: expected "1487811 ", got "0 " | |
| 17 | Apr 15, 2025 03:27 | 0 | 0 | 0 | 0 | 0 | Error: Exit with code 101: thread 'main' panicked at fenwick.rs:91:9: index out of bounds: the len is 950 but the index is 18446744073709551612 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace | stderr |
| 18 | Apr 15, 2025 03:26 | 0 | 0 | 0 | 0 | 0 | Error: Killed by timeout | |
| 19 | Apr 15, 2025 03:25 | 0 | 0 | 0 | 0 | 0 | Error: expected "1629839 ", got "0 " | |
| 20 | Apr 15, 2025 03:25 | 0 | 0 | 0 | 0 | 0 | Error: expected "1358611 ", got "0 " | |
| 21 | Apr 15, 2025 03:25 | 0 | 0 | 0 | 0 | 0 | Error: expected "2217015 ", got "0 " | |
| 22 | Apr 15, 2025 03:25 | 0 | 0 | 0 | 0 | 0 | Error: expected "2488876 ", got "0 " | |
| 23 | Apr 15, 2025 03:24 | 0 | 0 | 0 | 0 | 0 | Error: expected "3138781 ", got "0 " | |
| 24 | Apr 15, 2025 03:24 | 0 | 0 | 0 | 0 | 0 | Error: Exit with code 101: thread 'main' panicked at fenwick.rs:91:9: index out of bounds: the len is 950 but the index is 18446744073709551586 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace | stderr |