{"id":792,"date":"2013-08-09T03:04:18","date_gmt":"2013-08-08T19:04:18","guid":{"rendered":"http:\/\/www.shuizilong.com\/house\/?p=792"},"modified":"2013-08-09T17:52:02","modified_gmt":"2013-08-09T09:52:02","slug":"2013-multi-university-training-contest-6","status":"publish","type":"post","link":"https:\/\/www.shuizilong.com\/house\/archives\/2013-multi-university-training-contest-6\/","title":{"rendered":"2013 Multi-University Training Contest 6"},"content":{"rendered":"

1007. Message_Passing<\/h2>\n

Brief description: <\/h3>\n

… \u7ed9\u5b9a\u4e00\u4e2a\u65e0\u5411\u56fe\uff0c\u6bcf\u4e00\u4e2a\u4eba\u521d\u59cb\u6709\u4e00\u4e2a\u4fe1\u606f\uff0c\u6bcf\u4e00\u6b65\uff0c\u53ef\u4ee5\u9009\u62e9\u4e00\u4e2a\u4eba\u5c06\u5b83\u6240\u77e5\u7684\u6240\u6709\u4fe1\u606f\u544a\u8bc9\u7ed9\u4e0e\u5979\u76f8\u90bb\u7684\u53e6\u4e00\u4e2a\u4eba\u3002
\n\u3002\u3002\u8981\u4f7f\u5f97\u6700\u540e\u6bcf\u4e2a\u4eba\u90fd\u83b7\u5f97\u6240\u6709\u4eba\u7684\u4fe1\u606f\uff0c\u6700\u5c11\u9700\u8981\u591a\u5c11\u6b65\uff0c\u6ee1\u8db3\u6700\u5c11\u6b65\u6570\u6761\u4ef6\u4e0b\uff0c\u6709\u591a\u5c11\u79cd\u4e0d\u540c\u7684\u65b9\u6848\u3002
\n<\/p>\n

Analysis: <\/h3>\n

\u5bb9\u6613\u53d1\u73b0\u4fe1\u606f\u4e00\u5b9a\u662f\u5148\u5230\u4e00\u4e2a\u6c47\u70b9\uff0c\u518d\u4ece\u8fd9\u4e2a\u6c47\u70b9\u5206\u53d1\u51fa\u53bb\u3002\u3002<\/p>\n

\u8bbe F[u]<\/code> \u8868\u793a\u4ee5 u<\/code> \u4e3a\u6839\u7684\u5b50\u6811\uff0c\u6c47\u805a\u5230 u<\/code> \u70b9\u65f6\u7684\u65b9\u6848\u6570\u3002<\/p>\n

\r\nvoid dfs0(int u){\r\n    F[u] = sz[u] = 1; int cur = 0; REP_G(i, u){\r\n        del(i^1), dfs0(v);\r\n        sz[u] += sz[v], cur += sz[v];\r\n        F[u] *= F[v] * C(cur, sz[v]);\r\n    }\r\n}\r\n<\/pre>\n
\u8bbe P[u]<\/code> \u8868\u793a u<\/code> \u4e3a\u6839\u7684\u5b50\u6811\u5916\uff0c\u6c47\u805a\u5230 u<\/code> \u70b9\u65f6\u7684\u65b9\u6848\u6570\u3002
\n\u3002\u3002\u4e8e\u662f\u53ef\u4ee5\u901a\u8fc7\u53e6\u4e00\u4e2a dfs1() \u8fc7\u7a0b\uff0c\u6765\u907f\u514d\u679a\u4e3e\u8fd9\u4e2a\u6c47\u70b9\u3002<\/p>\n
\r\nvoid dfs1(int u){\r\n\r\n    res += sqr(P[u] * F[u] * C(n-1, sz[u]-1));\r\n\r\n    REP_G(i, u){\r\n        P[v] = P[u] * F[u] * C(n-sz[v]-1, n-sz[u]) \/ (F[v] * C(sz[u]-1, sz[v]));\r\n        \/\/cout << v << " " << F[v] << " " << P[v] << " "<< C(n-1, sz[v]-1) << endl;\r\n        dfs1(v);\r\n    }\r\n}\r\n<\/pre>\n
https:\/\/gist.github.com\/lychees\/6187521#file-message_passing-cpp<\/a><\/p>\n
\u8d5b\u540e\u819c\u62dc\u4e86 wzk \u5de8\u5de8\u7684\u4ee3\u7801\u3002\u3002<\/a>\u3002\u624d\u6ce8\u610f\u5230\u4e2d\u95f4\u7684 dp \u8fc7\u7a0b\u53ef\u4ee5\u5316\u7b80\u3002\u3002
\n\u3002\u3002\u3002\u4ee5 u<\/code> \u4e3a\u6c47\u70b9\u65f6\u3002\u3002\u65b9\u6848\u6570\u5c31\u662f\u3002\u3002\u3002 $$n!\/\\prod{{sz}_i}$$\u3002\u3002\uff08\u3002\u5c31\u662f \u6709\u5411\u6811 \u7684\u62d3\u6251\u6392\u5e8f\u65b9\u6848\u8ba1\u6570\u3002\u3002
\n\u3002\u3002\u4e8e\u662f\u5c31\u53d8\u5f97\u975e\u5e38\u597d\u5199\u4e86\u3002\u3002\u3002<\/p>\n
https:\/\/gist.github.com\/lychees\/6187521#file-message_passing2-cpp<\/a><\/p>\n
External link: <\/h3>\n
\u3002\u3002\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
1007. Message_Passing Brief description: … \u7ed9\u5b9a\u4e00\u4e2a\u65e0\u5411\u56fe\uff0c\u6bcf\u4e00\u4e2a\u4eba\u521d\u59cb\u6709\u4e00\u4e2a\u4fe1\u606f\uff0c\u6bcf\u4e00\u6b65\uff0c\u53ef\u4ee5\u9009\u62e9\u4e00\u4e2a\u4eba\u5c06\u5b83\u6240\u77e5\u7684\u6240\u6709\u4fe1\u606f\u544a\u8bc9\u7ed9\u4e0e\u5979\u76f8\u90bb\u7684\u53e6\u4e00\u4e2a\u4eba\u3002 \u3002\u3002\u8981\u4f7f\u5f97\u6700\u540e\u6bcf\u4e2a\u4eba\u90fd\u83b7\u5f97\u6240\u6709\u4eba\u7684\u4fe1\u606f\uff0c\u6700\u5c11\u9700\u8981\u591a\u5c11\u6b65\uff0c\u6ee1\u8db3\u6700\u5c11\u6b65\u6570\u6761\u4ef6\u4e0b\uff0c\u6709\u591a\u5c11\u79cd\u4e0d\u540c\u7684\u65b9\u6848\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":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false}}},"categories":[15],"tags":[],"class_list":["post-792","post","type-post","status-publish","format-standard","hentry","category-online"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p2tdP7-cM","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/792","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=792"}],"version-history":[{"count":1,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/792\/revisions"}],"predecessor-version":[{"id":793,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/792\/revisions\/793"}],"wp:attachment":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/media?parent=792"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/categories?post=792"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/tags?post=792"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}