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第19回オフラインリアルタイムどう書くの参考問題をPythonで解く

問題はこちら
http://nabetani.sakura.ne.jp/hena/ord19sanwa/

他の方々の回答はこちら
http://qiita.com/Nabetani/items/0a711729fdea28b1c30b

高速化版:

from itertools import chain, combinations_with_replacement as combi_r

def solve(d):
    n=map(int, d.split(','))
    s=set(n)
    a=[(x,y,z)
       for x in xrange(1, n[0]+1)
       for y in xrange(x, n[-1]+1)
       for z in xrange(max(y, n[-1]/3), n[-1]+1)
       if s == s&{sum(c) for c in chain(*[combi_r((x,y,z), r) for r in (1,2,3)])}]
    return not a and 'none' or a[1:] and 'many' or ','.join(map(str, a[0]))

最初の実装:

from itertools import *

def solve(d):
    n=map(int, d.split(','))
    s=set(n)
    a=[(x,y,z)
       for x in xrange(1, n[0]+1)
       for y in xrange(x, n[-1]+1)
       for z in xrange(y, n[-1]+1)
       if s == s&{sum(p) for p in chain(*[product((x,y,z), repeat=r) for r in (1,2,3)])}]
    return not a and 'none' or len(a)>1 and 'many' or ','.join(map(str, a[0]))

def test(data, correct):
    answer = solve(data)
    print 'xo'[answer == correct], data, correct, answer

0, test( "3,11,12,102,111,120", "1,10,100" );
1, test( "10,20,30,35,70", "many" );
2, test( "1,5,20,80", "none" );
3, test( "1,2,3,4,5,6,7,8,9,10,11,12,13,14", "many" );
4, test( "1,2,3,4,5,6,7,8,9,10,11,12,13,14,15", "1,4,5" );
5, test( "1,2,3,4,5,6,7,8,9,10,11,12,13,14,17", "none" );
6, test( "1,2,3,4,5,6,7,8,9,10,11,12,13,14,18", "1,4,6" );
7, test( "5,6,7,8,9,10,11,12,13,14,15,16", "2,5,6" );
8, test( "9,10,11,12,13,14,15,16,17,18,19", "4,5,7" );
9, test( "11,36,37,45,55,70,71", "1,10,35" );
10, test( "92,93,94,95,96,97,98,99", "30,32,33" );
11, test( "95,96,97,98,99,100", "many" );
12, test( "27,30,34,37,43,44,46,51,57", "10,17,23" );
13, test( "6,10,13,17,65,73,76,80", "none" );
14, test( "12,19,21,29,85", "none" );
15, test( "1,2,8,10,14,23,58,62,64", "none" );
16, test( "4,22,25,31,44,50,58,69,71,72,73,77", "none" );
17, test( "8,16,26,27,42,53,65,69,81,83,88,99", "none" );
18, test( "9,10,23,24,28,33,38,39,58,68,84", "none" );
19, test( "11,16,24,26,88", "none" );
20, test( "24,33,47,56,63,66,75,78,89,93", "none" );
21, test( "7,26,72,77", "many" );
22, test( "69,88,95,97", "many" );
23, test( "9,14,48,89", "many" );
24, test( "69,76,77,83", "many" );
25, test( "11,14,24", "many" );
26, test( "8,25,75,93", "many" );
27, test( "11,55,93,98,99", "many" );
28, test( "71,83,87", "many" );
29, test( "22,76,77,92", "7,15,62" );
30, test( "33,61,66,83,95", "17,33,61" );
31, test( "6,16,49,55,72", "6,16,33" );
32, test( "62,85,97,98", "12,25,73" );
33, test( "54,60,67,70,72", "20,25,27" );
34, test( "54,61,68,84,87", "27,30,34" );
35, test( "65,67,69,75,79,89,99", "21,23,33" );
36, test( "69,72,80,81,89", "23,24,33" );
37, test( "1,2,3", "many" );

高速化:

product((x,y,z), repeat=r)

combinations_with_replacement((x,y,z), r)

に変更することで、22秒だった実行時間が13秒になりました。
zの最小値は入力最大値の1/3なので、次のようにすると若干速くなりました。

for z in xrange(max(y, n[-1]/3), n[-1]+1)
shiracamus
元、低レイヤーエンジニア。 現、サイバーセキュリティ研究者。 使用言語は、C, Lisp, Java, Python, C#, JavaScript/Node.js。 経験アセンブリ言語は Z80, 6502, 6809, 68000, SPARC, PowerPC, ARM, x86/x64。
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