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December 15, 2015 04:39
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rust 0.6 (incoming branch) solution to google code jam practice problem "Store Credit"
http://code.google.com/codejam/contest/351101/dashboard
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fn main() { | |
let mut input = get_lines(); | |
let num_cases_str = vec::remove(&mut input, 0); | |
let num_cases = int::from_str(num_cases_str).get(); | |
let mut i = 1; | |
while i <= num_cases { | |
let credit = int::from_str(vec::remove(&mut input, 0)).get(); | |
let _num_items = int::from_str(vec::remove(&mut input, 0)).get(); | |
let items = vec::map(str::split_char(vec::remove(&mut input, 0), ' '), |&s| int::from_str(s).get()); | |
let (a, b) = best_buy(credit, items); | |
io::println(fmt!("Case #%d: %u %u", i, a, b)); | |
i += 1; | |
} | |
} | |
fn best_buy(credit: int, items: &[int]) -> (uint, uint) { | |
let buyable = vec::filtered(items, |&itm| itm <= credit); | |
let mut best_pair = (0, 1); | |
let mut best_total = 0; | |
let mut i = 0; | |
let mut j: uint; | |
while i < buyable.len() - 1 { | |
j = i + 1; | |
while j < buyable.len() { | |
let tmp_total = items[i] + items[j]; | |
if tmp_total <= credit && tmp_total > best_total { | |
best_pair = (i+1, j+1); | |
best_total = tmp_total; | |
} | |
j += 1; | |
} | |
i += 1; | |
} | |
best_pair | |
} | |
fn get_lines() -> ~[~str] { | |
let mut result = ~[]; | |
let reader = io::stdin(); | |
let util = @reader as @io::ReaderUtil; | |
while !reader.eof() { | |
result.push(util.read_line()); | |
} | |
result | |
} |
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In this problem you must grab 2 unique items (no more or less). So what looks like a dynamic programming problem at first is actually solved by simply searching all unique pairs. After eliminating unusable items, even google's large input file takes under a second.