{"id":532,"date":"2012-10-18T17:48:21","date_gmt":"2012-10-18T09:48:21","guid":{"rendered":"http:\/\/www.shuizilong.com\/house\/?p=532"},"modified":"2012-12-20T10:04:44","modified_gmt":"2012-12-20T02:04:44","slug":"acm-icpc-regional-asia-beijing-2008","status":"publish","type":"post","link":"https:\/\/www.shuizilong.com\/house\/archives\/acm-icpc-regional-asia-beijing-2008\/","title":{"rendered":"ACM-ICPC Regional Asia Beijing 2008"},"content":{"rendered":"<h3>Overview:<\/h3>\n<p>\u3002\u3002\u5e38\u89c4\u5957\u9898\u3002\u3002\u9664\u4e86 B \u9898\u4ee5\u5916\u90fd\u6ca1\u4ec0\u4e48\u597d\u63a8\u8350\u7684\u3002\u3002\u3002\u3002\uff08B \u9898\u662f\u975e\u5e38\u7ecf\u5178\u7684 Nim-like \u95ee\u9898\u3002\u3002\u5fc5\u987b\u603b\u7ed3\u6574\u7406\u3002\u3002\u3002\u3002<br \/>\nA \u53ef\u4ee5\u8fed\u4ee3\u52a0\u6df1\u641c\u7d22\u3001\u4e5f\u53ef\u4ee5\u7f51\u7edc\u6d41\u3002\u3002<br \/>\nG \u53ef\u4ee5\u6392\u5e8f\u8d2a\u5fc3\u3001\u4e5f\u53ef\u4ee5 2-SAT\u3002\u3002<br \/>\n\u3002\u53e6\u5916\u50cf\u662f J \u9898\u8fd9\u6837\u5b50\u7684\u8611\u83c7\u9898\u3002\u3002\u5904\u7406\u8d77\u6765\u5fc5\u987b\u8981\u975e\u5e38\u5c0f\u5fc3\u3002\u3002\u3002<br \/>\n\u3002\u3002\u6bd4\u8d5b\u7684\u65f6\u5019\u9700\u8981\u7528\u8fd9\u7c7b\u9898\u76ee\u6765\u7ed9\u4e09\u59b9\u4e89\u53d6\u63a8 B \u548c I \u7684\u65f6\u95f4\u3002\u3002\u3002<\/p>\n<p><!--more--><\/p>\n<h3>Analysis:<\/h3>\n<p>Problem A. Destroying the bus stations<br \/>\n..\u6709\u5411\u56fe\uff0c\u95ee\u6700\u5c11\u5220\u53bb\u591a\u5c11\u70b9\uff0c\u4f7f\u5f97\u4e0d\u5b58\u5728 s \u5230 t \u7684\u957f\u5ea6 <=k \u7684\u8def\u5f84\u3002\n\uff08\u3002\u4e0d\u80fd\u5220\u53bb s\u3001t\u3002\u3002\u4e0d\u5b58\u5728 s \u76f4\u63a5\u5230 t \u7684\u8fb9\u3002\u3002\u3002n \u2264 50\u3002\u3002\u3002\n\n\u3002\u3002\u56e0\u4e3a n \u6bd4\u8f83\u5c0f\u6240\u4ee5\u53ef\u4ee5\u88f8\u641c\u3002\u3002\u3002\n\u3002\u3002\u4e00\u822c\u95ee\u9898\u53ef\u4ee5\u7f51\u7edc\u6d41\u89e3\u51b3\u3002\uff08\u6709\u5411\u56fe\u70b9\u8fde\u901a\u5ea6\uff09\u3002\u3002\n\u3002\u505a\u6cd5\u662f\u5bf9\u4e2d\u95f4\u7ed3\u70b9\u62c6\u70b9\u3002\u8fde\u4e00\u6761\u5bb9\u91cf\u4e3a 1 \u7684\u8fb9\u3002\n\u3002\u3002\u4e4b\u540e\u4ece s \u51fa\u53d1\u5404\u505a\u4e00\u6b21\u5355\u6e90\u6700\u77ed\u8def\u3002\uff08\u5f97\u5230 d1[]\u3002\u3002\u3002\n\u3001\u4ece t \u51fa\u53d1\u5728\u8f6c\u7f6e\u56fe\u4e2d\u505a\u4e00\u6b21\u6700\u77ed\u8def\u3002\u3002(d2[]\u3002\u3002\n\u3002\u68c0\u67e5\u6bcf\u6761\u8fb9 (u, v, w)\u3002\u3002\u5982\u679c d1[u] + w + d2[v] <= k \n\u3002\u5219\u8fde\u4e00\u6761 u -> v&#8217; \u3002\u3002\u5bb9\u91cf\u4e3a oo \u7684\u8fb9\u3002\u3002\u6c42\u6700\u5c0f\u5272\u3002\u3002<\/p>\n<p>\u7b97\u6cd5 1\uff1a<br \/>\n<a href=\"http:\/\/acm.hust.edu.cn:8080\/judge\/problem\/viewSource.action?id=751230\">\u8fed\u4ee3\u52a0\u6df1\u641c\u7d22\u3002\u3002<\/a><br \/>\n\u7b97\u6cd5 2\uff1a<br \/>\n<a href=\"http:\/\/acm.hust.edu.cn:8080\/judge\/problem\/viewSource.action?id=867952\">\u6700\u5c0f\u5272\u3002<\/a><\/p>\n<p>Problem B. A simple stone game<br \/>\n\u4efb\u4f55\u4e00\u4e2a\u6b63\u6574\u6570\u90fd\u53ef\u4ee5\u5206\u89e3\u4e3a\u67d0\u4e2a\u7c7b Fibonacci \u6570\u5217 {ai} \u4e2d\u3002\u3002<br \/>\n\u4e00\u4e2a\u5b50\u5e8f\u5217 {aj} \u7684\u548c\u3002\u3002\u4e14\u6ee1\u8db3  k aj <   aj+1 \u3002\n\u8bc1\u660e\uff1a\uff08\u6784\u9020\n\u3002\u3002\u3002\u8bbe ri \u4e3a\u524d i \u4e2a {ai} \uff0c\u5728\u6ee1\u8db3\u6027\u8d28 1 \u7684\u60c5\u51b5\u4e0b\u6240\u80fd\u5206\u89e3\u51fa\u7684\u6570\u5b57\u7684\u6700\u5927\u503c\u3002\n\u90a3\u4e48\u6709\u3002\u3002\nai+1 = ri + 1\u3002\u3002\uff08\u4fdd\u8bc1\u6bcf\u4e2a\u6570\u5b57\u90fd\u53ef\u4ee5\u51fa\u73b0\u3002\u3002\nri = ai + rj\u3002\u3002j \u6ee1\u8db3 aj * k < ai \u4e14\u5c3d\u53ef\u80fd\u5927\u3002\uff08\u4fdd\u8bc1\u5206\u89e3\u65b9\u6848\u552f\u4e00\u3002\u3002\n\n\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\n\n\u8fd9\u4e2a\u9898\u975e\u5e38 Nice\uff0c\u601d\u7ef4\u6d41\u9996\u5148\u662f\u5bf9 k \u505a\u9650\u5236\uff0c\n\u5bf9\u4e8e k = 1\u30012 \u7684\u60c5\u51b5\u4e0d\u96be\u53d1\u73b0\u89e3\u548c\u6570\u7684\u4e8c\u8fdb\u5236\u5206\u89e3\u548c Fibonacci \u5206\u89e3\u6709\u5173\u3002\u3002\u3002\n\n\u5173\u4e8e Fibonacci \u552f\u4e00\u5206\u89e3\u8fd9\u4e2a\u6709\u5fc5\u8981\u5728 Mark \u4e00\u4e0b\u3002\u3002\n\n\u5b9a\u7406\uff1a\u4efb\u4f55\u4e00\u4e2a\u6b63\u6574\u6570\u90fd\u53ef\u4ee5\u5206\u89e3\u4e3a Fibonacci \u6570\u5217\u4e2d\u4e00\u4e9b\u4e0d\u76f8\u90bb\u7684\u6570\u7684\u548c\uff0c\u4e14\u5206\u89e3\u65b9\u6848\u552f\u4e00\u3002\n\u8bc1\u660e\u8fd9\u4e2a\u5b9a\u7406\u7684\u65b9\u6cd5\u548c\u524d\u9762\u66f4\u4e00\u822c\u7684\u6784\u9020\u6cd5\u7c7b\u4f3c\uff0c\u4e14\n\u4e14 k = 2 \u6070\u597d\u662f Fibonacci \u6570\u5217\uff0c\u53ea\u662f k aj < aj+1 \u8fd9\u4e2a\u6761\u4ef6\u4e2d k = 2 \u60c5\u51b5\u4e0b\u7684\u7279\u4f8b\u3002\u3002\n\n\u4e4b\u540e\u628a\u89c2\u5bdf\u4e86\u4e00\u4e0b k \u6bd4\u8f83\u5c0f\u60c5\u51b5\u4e0b\u7684 {ai} .. .\n\n\n\n<pre>\r\n1,2,4,8,16,32,64 .. .\r\n1,2,3,5,8,13,21,34 .. .\r\n1,2,3,4,6,8,11,15 .. .\r\n1,2,3,4,5,7,9,12,15,19,24,31,40,52 .. .\r\n1,2,3,4,5,6,7,8,10,12,15,18,22,27,33,41,51,63,78\r\n<\/pre>\n<p>k = 3 \u7684\u65f6\u5019\u662f<\/p>\n<p><a href=\"http:\/\/oeis.org\/A003411\">A003411<\/a> \uff08 <a href=\"http:\/\/oeis.org\/A003412\">A003412<\/a> \/ <a href=\"http:\/\/oeis.org\/A003413\">A003413<\/a><\/p>\n<p>\u5bf9\u4e8e\u4e4b\u540e\u7684 k >=3 \u3002\u3002\u90fd\u662f\u4ece\u6570\u5217\u7684\u67d0\u9879\u5f00\u59cb\uff08\u54ea\u9879\uff1f\u3002\u3002<br \/>\n\u6ee1\u8db3 a[n] = a[n-1] + a[n-k] \u3002\u3002<br \/>\n\uff08&#8230; \u800c\u5f00\u59cb\u524d\u9762\u7684\u5730\u65b9\u4f1a\u5076\u5c14\u5411\u524d\u9707\u8361\u4e00\u4e0b\u3002 a[n] = a[n-1] + a[n-k+?]\u3002\u3002\u3002<br \/>\n\uff08&#8230; \u4f3c\u4e4e\u6ca1\u4ec0\u4e48\u89c4\u5f8b\u3002\u3002\u3002<\/p>\n<p><a href=\"http:\/\/acm.hust.edu.cn:8080\/judge\/contest\/viewSource.action?id=774057\">\u535a\u5f08\u8bba\u3001\u6590\u6ce2\u90a3\u5951\u6570\u5217\u3001\u6784\u9020<\/a><\/p>\n<p>Problem C. Ugly Windows<br \/>\n<a href=\"http:\/\/acm.hust.edu.cn:8080\/judge\/problem\/viewSource.action?id=754757\">\u6a21\u62df\u3002\u3002<\/a><\/p>\n<p>Problem D. Tornado<br \/>\n<a href=\"http:\/\/acm.hust.edu.cn:8080\/judge\/problem\/viewSource.action?id=770094\">\u8ba1\u7b97\u51e0\u4f55\u3002\u3002<\/a><br \/>\n\u56fa\u5b9a\u4e00\u70b9\uff0c\u95ee\u9898\u8f6c\u6362\u4e3a\u5355\u70b9\u5230\u4e00\u7ec4\u5e73\u884c\u7ebf\u6bb5\u7684\u6700\u77ed\u8ddd\u79bb\uff0c\u4e09\u5206\u4e4b\u3002\u3002<br \/>\n\u6ce8\u610f\u7ebf\u6bb5\u9000\u5316\u7684\u60c5\u51b5\u3002\u3002\u3002\u3002<\/p>\n<p>Problem E. Minimal Ratio Tree<br \/>\n<a href=\"http:\/\/acm.hust.edu.cn:8080\/judge\/problem\/viewSource.action?id=772788\">\u66b4\u529b\u679a\u4e3e\uff0c\u6700\u5c0f\u751f\u6210\u6811\u3002<\/a><\/p>\n<p>Problem F.<br \/>\n<a href=\"http:\/\/acm.hust.edu.cn:8080\/judge\/contest\/viewSource.action?id=774456\">\u5355\u8c03\u961f\u5217\uff0c\u52a8\u6001\u89c4\u5212\u3002\u3002\u3002<\/a><\/p>\n<p>Problem G. Priest John&#8217;s Busiest Day<br \/>\n\u6839\u636e\u4e2d\u95f4\u65f6\u523b\u6392\u5e8f\u8d2a\u5fc3\u5373\u53ef\u3002\uff08\u5a5a\u793c\u5fc5\u7136\u7ecf\u8fc7\u4e2d\u95f4\u65f6\u523b\u3002\u3002\u6ce8\u610f\u4eea\u5f0f\u65f6\u95f4\u4e25\u683c\u5927\u4e8e\u5a5a\u793c\u65f6\u95f4\u7684\u4e00\u534a\u3002\u3002<br \/>\n<a href=\"http:\/\/acm.hust.edu.cn:8080\/judge\/problem\/viewSource.action?id=773051\">\u6392\u5e8f\uff0c\u8d2a\u5fc3\u3002\u3002<\/a><\/p>\n<p>Problem H. Ping pong<br \/>\n<a href=\"http:\/\/acm.hust.edu.cn:8080\/judge\/problem\/viewSource.action?id=754839\">\u6811\u72b6\u6570\u7ec4\u3002\u3002\u3002<\/a><\/p>\n<p>Problem I. Timer<br \/>\n<a href=\"http:\/\/acm.hust.edu.cn:8080\/judge\/contest\/viewSource.action?id=754874\">\u4e8c\u5206\u7b54\u6848 + \u79ef\u5206 =w=\u3002\u3002\u3002<\/a><\/p>\n<p>Problem J. Elevator<br \/>\n1 \u662f\u5982\u4f55\u8ba8\u8bba\u72b6\u6001\u3002\u3002\u3002<br \/>\n\u3002\u3002\u603b\u4e4b\u5206 idle(\u7a7a\u95f2\u4e2d)\u3002\u3002 anchor (\u505c\u6cca\u4e2d) \u3002\u3002open (\u5f00\u95e8\u4e2d) \u4e09\u79cd\u8fdb\u884c\u8ba8\u8bba\u3002\u3002<br \/>\n\u3002\u3002\u53e6\u5916\u5bf9\u4e8e\u7a7a\u95f2\u72b6\u6001\u3002\u3002\u8bb0\u5f55\u5f53\u524d\u79fb\u52a8\u7684\u65b9\u5411\u3002\u3002<br \/>\n\uff08\u6b63\u786e\u7684\u8ba8\u8bba\u72b6\u6001\u975e\u5e38\u91cd\u8981\u3002\u3002\u5426\u5219\u6839\u672c\u65e0\u6cd5\u5904\u7406\u8bf8\u5982\u3002\u3002\u5148\u5f00\u95e8\u8fdb\u6765 3 \u4e2a\u4eba\u3002\u3002\u8fd9\u4e2a\u65f6\u5019\u53c8\u6765\u4e86 1 \u4e2a\u3002\u3002\u3002\u518d\u8fdb\u6765 1 \u4e2a\u3002\u3002\u518d\u5173\u95e8\u3002\u3002\u5173\u95e8\u7684\u65f6\u5019\u53c8\u6765\u4e86\u4e00\u4e2a\u3002\u3002\u518d\u5f00\u95e8\u518d\u8fdb\u6765\u4e00\u4e2a\u8fd9\u6837\u7684\u60c5\u51b5\u3002\u3002\u3002\uff09<\/p>\n<p>2 \u5904\u7406\u8bf7\u6c42\u7684\u4f18\u5148\u7ea7\u95ee\u9898\u3002\u3002<br \/>\n\u3002\u3002\u8fd9\u91cc\u505a\u4e86\u3002\u3002__c(), _c(), c0(), c1(), c2(), c3() \u4e00\u7ec4\u51fd\u6570\u3002\u3002\u3002<br \/>\n__c() \u5224\u65ad\u67d0\u4e2a\u4f4d\u7f6e\u662f\u5426\u6709\u4eba\u8981\u4e0a\u8f66\u3002\u3002<br \/>\n_c() \u5728 __c() \u7684\u57fa\u7840\u4e0a\uff0c\u518d\u5224\u65ad\u8bf7\u6c42\u65b9\u5411\u662f\u5426\u4e0e\u7535\u68af\u8fd0\u884c\u65b9\u5411\u4e00\u81f4\u3002<br \/>\nc0(), c1(), c2(), c3() \u5206\u522b\u662f\u662f\u5426\u6709 \u4e0a\/\u4e0b \u65b9\u5411\u7684\u4eba\u9700\u8981 \u8fdb\/\u51fa\u3002\u3002\u3002                           <\/p>\n<p>\u3002\u3002\u7136\u540e\u505a\u8d77\u6765\u7684\u8bdd\u5c31\u8981\u8212\u670d\u591a\u4e86\u3002\u3002<br \/>\n<a href=\"http:\/\/acm.hust.edu.cn:8080\/judge\/problem\/viewSource.action?id=767978\">\u6076\u6a21\u62df\u3002\u3002<\/a><\/p>\n<h3>External link: <\/h3>\n<p><a href=\"http:\/\/acm.hust.edu.cn:8080\/judge\/contest\/view.action?cid=723#overview\">http:\/\/acm.hust.edu.cn:8080\/judge\/contest\/view.action?cid=723#overview<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview: \u3002\u3002\u5e38\u89c4\u5957\u9898\u3002\u3002\u9664\u4e86 B \u9898\u4ee5\u5916\u90fd\u6ca1\u4ec0\u4e48\u597d\u63a8\u8350\u7684\u3002\u3002\u3002\u3002\uff08B \u9898\u662f\u975e\u5e38\u7ecf\u5178\u7684 Nim-like \u95ee\u9898\u3002\u3002\u5fc5\u987b\u603b\u7ed3\u6574\u7406\u3002\u3002\u3002\u3002 A \u53ef\u4ee5\u8fed\u4ee3\u52a0\u6df1\u641c\u7d22\u3001\u4e5f\u53ef\u4ee5\u7f51\u7edc\u6d41\u3002\u3002 G \u53ef\u4ee5\u6392\u5e8f\u8d2a\u5fc3\u3001\u4e5f\u53ef\u4ee5 2-SAT\u3002\u3002 \u3002\u53e6\u5916\u50cf\u662f J \u9898\u8fd9\u6837\u5b50\u7684\u8611\u83c7\u9898\u3002\u3002\u5904\u7406\u8d77\u6765\u5fc5\u987b\u8981\u975e\u5e38\u5c0f\u5fc3\u3002\u3002\u3002 \u3002\u3002\u6bd4\u8d5b\u7684\u65f6\u5019\u9700\u8981\u7528\u8fd9\u7c7b\u9898\u76ee\u6765\u7ed9\u4e09\u59b9\u4e89\u53d6\u63a8 B \u548c I \u7684\u65f6\u95f4\u3002\u3002\u3002<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false}}},"categories":[1],"tags":[],"class_list":["post-532","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p2tdP7-8A","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/532","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/comments?post=532"}],"version-history":[{"count":1,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/532\/revisions"}],"predecessor-version":[{"id":533,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/532\/revisions\/533"}],"wp:attachment":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/media?parent=532"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/categories?post=532"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/tags?post=532"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}