{"id":2027,"date":"2022-09-10T06:22:04","date_gmt":"2022-09-09T22:22:04","guid":{"rendered":"https:\/\/www.shuizilong.com\/house\/?p=2027"},"modified":"2022-09-10T08:29:09","modified_gmt":"2022-09-10T00:29:09","slug":"codeforces-round-819","status":"publish","type":"post","link":"https:\/\/www.shuizilong.com\/house\/archives\/codeforces-round-819\/","title":{"rendered":"Codeforces Round #819"},"content":{"rendered":"<ul>\n<li><a href=\"https:\/\/codeforces.com\/contest\/1726\">https:\/\/codeforces.com\/contest\/1726<\/a><\/li>\n<li><a href=\"https:\/\/zhuanlan.zhihu.com\/p\/562689105\">https:\/\/zhuanlan.zhihu.com\/p\/562689105<\/a><\/li>\n<\/ul>\n<h2>C. Jatayu&#8217;s Balanced Bracket Sequence<\/h2>\n<p>\u8c03\u6574\u6cd5\u3002<br \/>\n\u57fa\u7840\u60c5\u51b5\u662f ((()))\u3002\u3002\u8fde\u901a\u5206\u91cf\u4e3a n\u3002\u6211\u4eec\u89c2\u5bdf\u4ec0\u4e48\u60c5\u51b5\u4e0b\u8fde\u901a\u5206\u91cf\u4f1a\u51cf\u5c11\u3002<br \/>\n(()())\u3002\u3002\u6bd4\u5982\u8fd9\u6837\u3002\u3002\u6761\u4ef6\u662f\u4e4b\u524d\u51fa\u73b0\u8fc7\u5c42\u7ea7\u4e00\u6837\u7684\u62ec\u53f7\u5e8f\u5217\u4f7f\u5f97\u4ee5\u5f53\u524d\u4f4d\u7f6e\u7ed3\u5c3e\u7684\u5408\u6cd5\u5e8f\u5217\u4e0d\u6b62\u4e00\u7ec4\u3002<br \/>\n\u4e8e\u662f\u53ea\u8981\u5f00\u4e2a bool \u6570\u7ec4\u8bb0\u5f55\u4e00\u4e0b\u54ea\u4e9b\u5c42\u7ea7\u51fa\u73b0\u8fc7\u5c31\u597d\u4e86\uff0c\u5f53\u7136\u5f39\u6808\u7684\u65f6\u5019\u8981\u6062\u590d\u3002<\/p>\n<h2>D. Edge Split<\/h2>\n<p>\u9996\u5148\u8003\u8651\u6811\u7684\u60c5\u51b5\uff0c\u53d1\u73b0\u65e0\u8bba\u5982\u4f55\u67d3\u8272\u90fd\u4e0d\u5f71\u54cd\u7ed3\u679c\u3002<br \/>\n\u5f97\u77e5\u6211\u4eec\u6bcf\u6761\u8fb9\u67d3\u8272\u7684\u76ee\u7684\uff0c\u662f\u51cf\u5c11\u5bf9\u5e94\u989c\u8272\u7684\u4e00\u4e2a\u8fde\u901a\u5206\u91cf\u3002<br \/>\n\u56e0\u6b64\u6211\u4eec\u8003\u8651\u5c06\u5176\u4e2d\u4e00\u79cd\u67d3\u8272\u56fa\u5b9a\u6210\u4e00\u9897\u751f\u6210\u6811\uff0c\u8fd9\u6837\u53ea\u8981\u4fdd\u8bc1\u591a\u51fa\u7684\u8fb9\u4e0d\u6784\u6210\u4e00\u4e2a\u73af\u5373\u53ef\u3002<br \/>\n\u800c\u8fd9\u5728\u53ea\u6709 3 \u6761\u989d\u5916\u8fb9\u7684\u60c5\u51b5\u4e0b\u603b\u662f\u53ef\u4ee5\u4fdd\u8bc1\u7684\u3002<\/p>\n<h2>E. Almost Perfect<\/h2>\n<p>\u7edf\u8ba1\u957f\u5ea6\u4e3a n \u7684\u7f6e\u6362\u4e2d\uff0c\u6ee1\u8db3 $\\lvert p_i &#8211; p^{-1}_i \\rvert \\le 1$ \u7684\u7f6e\u6362\u7684\u6570\u76ee\u3002<\/p>\n<p>\u5bf9\u6ee1\u8db3\u6761\u4ef6\u7684\u7f6e\u6362\u8fdb\u884c\u5faa\u73af\u5206\u89e3\uff0c\u53ea\u6709\u4e09\u79cd\u60c5\u51b5\uff0c(i) (i,j) (i,j,i+1,j+1)\u3002<br \/>\n\u4e0d\u8003\u8651 4 \u7684\u60c5\u51b5\uff0c\u53ef\u4ee5\u679a\u4e3e 2 \u7684\u6570\u76ee\uff0c\u4e24\u4e24\u914d\u5bf9\uff0c\u65b9\u6848\u662f\uff1a<br \/>\n$$\\Sigma \\frac{i!}{j! * (i-2*j)! * 2^j}$$<br \/>\n\u4e5f\u53ef\u4ee5\u7528\u7c7b\u4f3c\u65af\u7279\u6797\u6570\u7684\u65b9\u6cd5\u5f97\u5230\u5730\u63a8\u516c\u5f0f\u3002<\/p>\n<p>\u9884\u5904\u7406\u8fd9\u4e2a\u5728\u679a\u4e3e 4 \u7684\u6570\u76ee\u5373\u53ef\u3002<\/p>\n<h2>F. Late For Work<\/h2>\n<p>\u9898\u610f\uff1a\u4e00\u6761\u76f4\u7ebf\uff0c\u8868\u793a\u4e00\u6761\u8def\u3002\u76f4\u7ebf\u4e0a\u6709 n \u4e2a\u70b9\uff0c\u8868\u793a n \u4e2a\u7ea2\u7eff\u706f\u3002\u6240\u6709\u7ea2\u7eff\u706f\u7684\u5468\u671f\u90fd\u662f t\uff0c\u7b2c i \u4e2a\u7ea2\u7eff\u706f\u7684\u5468\u671f\u8d77\u70b9\u662f\uff0c\u5b83\u5728\u6bcf\u4e2a\u5468\u671f\u7684\u524d gi \u79d2\u4e3a\u7eff\u706f\uff0c\u540e t &#8211; gi \u79d2\u4e3a\u7ea2\u706f\u3002\u5373\u5728\u6bcf\u4e2a\u5468\u671f\u4e2d [0, gi) \u65f6\u95f4\u65f6\u4e3a\u7eff\u706f\uff0c(gi, t] \u4e3a\u7ea2\u706f\u3002\u4ece\u7b2ci\u4e2a\u7ea2\u7eff\u706f\u5230i+1\u4e2a\u7ea2\u7eff\u706f\u6240\u9700\u7684\u65f6\u95f4\u4e3a di\u3002\u4f60\u53ef\u4ee5\u4ece\u4efb\u610f\u65f6\u95f4\u5f00\u59cb\uff0c\u95ee\u4ece\u7b2c\u4e00\u4e2a\u7ea2\u7eff\u706f\u5f00\u59cb\uff0c\u9700\u8981\u591a\u5c11\u65f6\u95f4\u53ef\u4ee5\u7a7f\u8d8a\u8fd9 n \u4e2a\u7ea2\u7eff\u706f\u3002<\/p>\n<p>\u5370\u8c61\u4e2d 14 \u5e74\u591a\u6821\u9547\u6d77\u4e2d\u5b66 Round\uff0c\u548c SRM rng_58 \u65f6\u4ee3\u90fd\u5404\u51fa\u8fc7\u7c7b\u4f3c\u7684\u95ee\u9898\u3002\u3002\u3002<br \/>\nhttps:\/\/vjudge.net\/problem\/HDU-4881<\/p>\n","protected":false},"excerpt":{"rendered":"<p>https:\/\/codeforces.com\/contest\/1726 https:\/\/zhuanlan.zhihu.com\/p\/562689105 C. Jatayu&#8217;s Balanced Bracket Sequence \u8c03\u6574\u6cd5\u3002 \u57fa\u7840\u60c5\u51b5\u662f ((()))\u3002\u3002\u8fde\u901a\u5206\u91cf\u4e3a n\u3002\u6211\u4eec\u89c2\u5bdf\u4ec0\u4e48\u60c5\u51b5\u4e0b\u8fde\u901a\u5206\u91cf\u4f1a\u51cf\u5c11\u3002 (()())\u3002\u3002\u6bd4\u5982\u8fd9\u6837\u3002\u3002\u6761\u4ef6\u662f\u4e4b\u524d\u51fa\u73b0\u8fc7\u5c42\u7ea7\u4e00\u6837\u7684\u62ec\u53f7\u5e8f\u5217\u4f7f\u5f97\u4ee5\u5f53\u524d\u4f4d\u7f6e\u7ed3\u5c3e\u7684\u5408\u6cd5\u5e8f\u5217\u4e0d\u6b62\u4e00\u7ec4\u3002 \u4e8e\u662f\u53ea\u8981\u5f00\u4e2a bool \u6570\u7ec4\u8bb0\u5f55\u4e00\u4e0b\u54ea\u4e9b\u5c42\u7ea7\u51fa\u73b0\u8fc7\u5c31\u597d\u4e86\uff0c\u5f53\u7136\u5f39\u6808\u7684\u65f6\u5019\u8981\u6062\u590d\u3002 D. Edge Split \u9996\u5148\u8003\u8651\u6811\u7684\u60c5\u51b5\uff0c\u53d1\u73b0\u65e0\u8bba\u5982\u4f55\u67d3\u8272\u90fd\u4e0d\u5f71\u54cd\u7ed3\u679c\u3002 \u5f97\u77e5\u6211\u4eec\u6bcf\u6761\u8fb9\u67d3\u8272\u7684\u76ee\u7684\uff0c\u662f\u51cf\u5c11\u5bf9\u5e94\u989c\u8272\u7684\u4e00\u4e2a\u8fde\u901a\u5206\u91cf\u3002 \u56e0\u6b64\u6211\u4eec\u8003\u8651\u5c06\u5176\u4e2d\u4e00\u79cd\u67d3\u8272\u56fa\u5b9a\u6210\u4e00\u9897\u751f\u6210\u6811\uff0c\u8fd9\u6837\u53ea\u8981\u4fdd\u8bc1\u591a\u51fa\u7684\u8fb9\u4e0d\u6784\u6210\u4e00\u4e2a\u73af\u5373\u53ef\u3002 \u800c\u8fd9\u5728\u53ea\u6709 3 \u6761\u989d\u5916\u8fb9\u7684\u60c5\u51b5\u4e0b\u603b\u662f\u53ef\u4ee5\u4fdd\u8bc1\u7684\u3002 E. Almost Perfect \u7edf\u8ba1\u957f\u5ea6\u4e3a n \u7684\u7f6e\u6362\u4e2d\uff0c\u6ee1\u8db3 $\\lvert p_i &#8211; p^{-1}_i \\rvert \\le 1$ \u7684\u7f6e\u6362\u7684\u6570\u76ee\u3002 \u5bf9\u6ee1\u8db3\u6761\u4ef6\u7684\u7f6e\u6362\u8fdb\u884c\u5faa\u73af\u5206\u89e3\uff0c\u53ea\u6709\u4e09\u79cd\u60c5\u51b5\uff0c(i) (i,j) (i,j,i+1,j+1)\u3002 \u4e0d\u8003\u8651 4 \u7684\u60c5\u51b5\uff0c\u53ef\u4ee5\u679a\u4e3e 2 \u7684\u6570\u76ee\uff0c\u4e24\u4e24\u914d\u5bf9\uff0c\u65b9\u6848\u662f\uff1a $$\\Sigma \\frac{i!}{j! * (i-2*j)! * 2^j}$$ \u4e5f\u53ef\u4ee5\u7528\u7c7b\u4f3c\u65af\u7279\u6797\u6570\u7684\u65b9\u6cd5\u5f97\u5230\u5730\u63a8\u516c\u5f0f\u3002 \u9884\u5904\u7406\u8fd9\u4e2a\u5728\u679a\u4e3e 4 [&hellip;]<\/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":[1],"tags":[],"class_list":["post-2027","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p2tdP7-wH","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/2027","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=2027"}],"version-history":[{"count":1,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/2027\/revisions"}],"predecessor-version":[{"id":2028,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/2027\/revisions\/2028"}],"wp:attachment":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/media?parent=2027"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/categories?post=2027"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/tags?post=2027"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}