プログラミングコンテストについての紹介と基本的なアルゴリズムについての解説です. 以下のリソースからかなりの部分を引用させていただいております. 大変感謝いたします. * プログラミングコンテストチャレンジブック http://www.amazon.co.jp/%E3%83%97%E3%83%AD%E3%82%B0%E3%83%A9%E3%83%9F%E3%83%B3%E3%82%B0%E3%82%B3%E3%83%B3%E3%83%86%E3%82%B9%E3%83%88%E3%83%81%E3%83%A3%E3%83%AC%E3%83%B3%E3%82%B8%E3%83%96%E3%83%83%E3%82%AF-%E7%A7%8B%E8%91%89-%E6%8B%93%E5%93%89/dp/4839931992 *

1. Hacks
@cou929

2. Agenda
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4. @cou929
• ( )
• web
• Web technologies
• HTML + CSS + JavaScript

6. •
•
• a.k.a.
•
•
• etc.

7. .
n . ,
4 . m
. .
, ,
. k_1, k_2, ..., k_n
, m ,
”Yes”, ”No” .
1 <= n <= 50
1 <= m <= 10^8
1 <= k_i <= 10^8
• 1-1

8. • n = 3, m = 10, k = {1, 2, 3, 5}
• “Yes” ({1, 1, 3, 5} )
• n = 3, m = 9, k = {1, 3, 5}
• “No”

10. •
•
•
•

11. •
•
•4
• n 50
• 1 <= n <= 1000 ?

13. TopCoder
• ( 2, 3 )
• !
• 1 2 3
• (C++, Java, C#, VB)
•
• TopCoder
•
• NASA
• http://www.topcoder.com/tc

14. Google Code Jam
•
• 2 3
• 2
•
• Google
• ?
• http://code.google.com/codejam

15. ACM ICPC
•
•
•
•
• ><
• http://cm.baylor.edu/welcome.icpc

16. • CodeForces
• http://codeforces.ru/
• CodeChef
• http://www.codechef.com/
• ICFP Programing Contest
• http://icfpcontest.org/
• etc.

17. • ,
• ICPC
•
•
•
•

18. • PKU Judge Online
• http://acm.pku.edu.cn/JudgeOnline/
• Sphere online judge
• http://www.spoj.pl/
• AIZU Online Judge
• http://rose.u-aizu.ac.jp/onlinejudge/

20. •
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•
•

21. •
• , ,
•
•
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•
•

22. •
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•

23. • “ ”
•
•
,
•

25. •
•
•

26. • -> -> ! ->
• -> -> !
•
•

27. • -> ->
-> -> ->
->
•
•

28. •
• O-
•
•

29. O-
•
• O(log n), O(n^3)
•
•
•
• 3 -> O(n^3) !
•
• .

30. • ,n 50
• O(n^4)
• 6,250,000

31. • 2
1,000,000
100,000,000
1,000,000,000

32. •
•
• (dfs)
• (bfs)
•
•
•

33. :
• O(n^4)
• n=3
n1 n2 n3
n1 n2 n3 n1 n2 n3 n1 n2 n3
n1 n2 n3 n1 n2 n3 ……
……

34. • http://www.itmedia.co.jp/enterprise/articles/1001/16/news001.html

35. • ,
•
•

36. :
a1, a2, ..., an . ,
k .
1 <= n <= 20
- 10^8 <= a_i <= 10^8
- 10^8 <= k <= 10^8
n=4
a = {1, 2, 4, 7}
k = 13
"Yes" (2 + 4 + 7)
• 2-1

37. • a_i , /
• a_i
• O(2^n)
•n 20
• 2 ^ 20 = 1,048,576

39. • “ : - ” (http://
www.itmedia.co.jp/enterprise/articles/1001/16/news001.html)

40. •
• dfs
•
• dfs bfs
•
• O( * )

41. :
•
:
• http://okajima.air-
nifty.com/b/2010/01/
post-abc6.html

42. :
, N, M .
N = M = 50
• http://okajima.air-nifty.com/b/2010/01/post-abc6.html

43. :
**************************
*S* * *
* * * * ************* *
* * * ************ *
* * *
************** ***********
* *
** ***********************
* * G *
* * *********** * *
* * ******* * *
* * *
**************************
• http://okajima.air-nifty.com/b/2010/01/post-abc6.html

44. :
**************************
*S* * $$$ *
*$* *$$*$ ************* *
*$* $$* $$$************ *
*$$$$* $$$$$ *
**************$***********
* $$$$$$$$$$$$$ *
**$***********************
* $$$$$*$$$$$$$$$$$$$$G *
* * $$$ *********** * *
* * ******* * *
* * *
**************************
• http://okajima.air-nifty.com/b/2010/01/post-abc6.html

45. • N*M
• 4
• O(N * M * 4)
• 50 * 50 * 4 = 10,000

47. • ,
• :
• m
• dfs bfs
•

48. • Binary Search
•
• O(log(n))

49. • http://www.gutterbucket.com/general-code/binary-search.html

50. • Dynamic Programming, DP
• ,
•

51. :
w v N , W
. , W ,
.
• “ALGORITHM NOTE ” (http://algorithms.blog55.fc2.com/
blog-entry-85.html)

52. •N /
2
• O(2^N)
•N 100 , 2^100 = 10^30

53. DP
• (N+1) * (W+1) C
• C[i][w] w 0
i

54. • C[i][w] 2
• C[i - 1][w - i ]+ i
• C[i - 1][w]

55. • “ALGORITHM NOTE ” (http://algorithms.blog55.fc2.com/
blog-entry-85.html)

56. • “ALGORITHM NOTE ” (http://algorithms.blog55.fc2.com/
blog-entry-85.html)

57. • “ALGORITHM NOTE ” (http://algorithms.blog55.fc2.com/
blog-entry-85.html)

58. • “ALGORITHM NOTE ” (http://algorithms.blog55.fc2.com/
blog-entry-85.html)

59. • “ALGORITHM NOTE ” (http://algorithms.blog55.fc2.com/
blog-entry-85.html)

60. • “ALGORITHM NOTE ” (http://algorithms.blog55.fc2.com/
blog-entry-85.html)

61. • “ALGORITHM NOTE ” (http://algorithms.blog55.fc2.com/
blog-entry-85.html)

62. • “ALGORITHM NOTE ” (http://algorithms.blog55.fc2.com/
blog-entry-85.html)

63. • “ALGORITHM NOTE ” (http://algorithms.blog55.fc2.com/
blog-entry-85.html)

64. • (N+1) * (W+1)
• O(NW)
•

65. DP
• ,
•

66. DP
•
•
•
•
• etc...

67. • Greedy Algorithm
• ,
•
•
•

68. :
100
• “ : - ”
(http://www.itmedia.co.jp/enterprise/articles/1009/04/news002.html)

69. Greedy
• ,
• 15436 = {10000, 5000, 100, 100, 100,
100, 10, 10, 10, 5, 1}

70. • {1, 6, 13}
• 18
• {13, 1, 1, 1, 1, 1}
• {6, 6, 6}

71. •
•
•
•

72. •
•
•
•
•
•
• etc...

73. • TopCoder
•
•
• http://topcoder.g.hatena.ne.jp/keyword/Challenge
• ,

74. •0
•
•
•
•

76. • 3
• @iwiwi, @wata_orz, @kita__masa
•
•
• http://www.amazon.co.jp/
-
- /dp/4839931992

77. •
•

78. Algorithm Tutorials
• TopCoder
•
•
•
• http://www.topcoder.com/tc?
module=Static&d1=tutorials
&d2=alg_index

79. • chokudai
• Imagine Cup 3
•
•
,
• http://www.itmedia.co.jp/
keywords/algorithmer.html

80. • @kinaba
• DP
• http://www.kmonos.net/
wlog/89.html#_2049080923
• http://www.kmonos.net/
wlog/90.html#_1712081024
• http://www.kmonos.net/
wlog/91.html#_2024081109

81. • @kinaba topcoder-jp
• http://twitter.com/#/list/kinaba/topcoder-jp
•
• ( )
• http://topcoder.g.hatena.ne.jp/
•
• 60

82. • Introduction To TopCoder, TopCoder
• http://d.hatena.ne.jp/cou929_la/
20091005/1254725798
•
• http://d.hatena.ne.jp/cou929_la/
20100708/1278600922