{"id":2975,"date":"2023-06-05T04:12:46","date_gmt":"2023-06-04T20:12:46","guid":{"rendered":"https:\/\/www.shuizilong.com\/house\/?p=2975"},"modified":"2023-06-05T04:14:41","modified_gmt":"2023-06-04T20:14:41","slug":"luogu-p3647-apio2014-%e8%bf%9e%e7%8f%a0%e7%ba%bf","status":"publish","type":"post","link":"https:\/\/www.shuizilong.com\/house\/archives\/luogu-p3647-apio2014-%e8%bf%9e%e7%8f%a0%e7%ba%bf\/","title":{"rendered":"Luogu P3647. [APIO2014] \u8fde\u73e0\u7ebf"},"content":{"rendered":"<ul>\n<li><a href=\"https:\/\/www.luogu.com.cn\/problem\/P3647\">https:\/\/www.luogu.com.cn\/problem\/P3647<\/a><\/li>\n<li><a href=\"https:\/\/oj.uz\/problem\/view\/APIO14_beads\">https:\/\/oj.uz\/problem\/view\/APIO14_beads<\/a><\/li>\n<\/ul>\n<p>\u65e0\u6839\u6811\u4e0d\u592a\u597d\u8bbe\u8ba1\u72b6\u6001\uff0c\u60f3\u529e\u6cd5\u8f6c\u6210\u6709\u6839\u6811\uff0c\u7136\u540e\u7528\u5b50\u6811\u66ff\u6362\u5927\u6cd5\u3002<br \/>\n\u518d\u8dd1\u6362\u6839 dp\u3002<br \/>\n\u6211\u6c38\u8fdc\u7231\u5b8f\u3002<\/p>\n<pre class=\"brush: cpp; light: false; title: ; toolbar: true; notranslate\" title=\"\">\r\n#include &lt;lastweapon\/io&gt;\r\nusing namespace lastweapon;\r\n\r\nconst int N = int(2e5) + 9;\r\n\r\nint d&#x5B;N]&#x5B;2], e&#x5B;N]&#x5B;2], z;\r\nVII adj&#x5B;N];\r\nint n;\r\n\r\n#define dv (max(d&#x5B;v]&#x5B;0], d&#x5B;v]&#x5B;1] + w))\r\n#define tv ((d&#x5B;v]&#x5B;0] + w) - dv)\r\n#define dp (max(e&#x5B;u]&#x5B;0], e&#x5B;u]&#x5B;1] + pw))\r\n#define tp ((e&#x5B;u]&#x5B;0] + pw) - dp)\r\n\r\nvoid dfs1(int u = 1, int p = 0) {\r\n    int t = -INF;\r\n    for (auto _: adj&#x5B;u]) {\r\n        int v = _.fi; if (v == p) continue; int w = _.se;\r\n        dfs1(v, u); d&#x5B;u]&#x5B;0] += dv;\r\n        checkMax(t, tv);\r\n    }\r\n    d&#x5B;u]&#x5B;1] = d&#x5B;u]&#x5B;0] + t;\r\n}\r\n\r\nvoid dfs2(int u = 1, int p = 0, int pw = -INF) {\r\n\r\n    checkMax(z, d&#x5B;u]&#x5B;0] + dp);\r\n\r\n    int t0 = tp, t1 = -INF, v0 = -1;\r\n    for (auto _: adj&#x5B;u]) {\r\n        int v = _.fi; if (v == p) continue; int w = _.se;   if (tv &gt; t0) t1 = t0, t0 = tv, v0 = v;\r\n        else if (tv &gt; t1) t1 = tv;\r\n    }\r\n\r\n    for (auto _: adj&#x5B;u]) {\r\n        int v = _.fi; if (v == p) continue; int w = _.se;\r\n        e&#x5B;v]&#x5B;0] = d&#x5B;u]&#x5B;0] - dv + dp;\r\n        e&#x5B;v]&#x5B;1] = e&#x5B;v]&#x5B;0] + (v0 == v ? t1 : t0);\r\n        dfs2(v, u, w);\r\n    }\r\n}\r\n\r\nint main() {\r\n\r\n#ifndef ONLINE_JUDGE\r\n    freopen(&quot;in.txt&quot;, &quot;r&quot;, stdin);\r\n    \/\/freopen(&quot;\/Users\/minakokojima\/Documents\/GitHub\/ACM-Training\/Workspace\/out.txt&quot;, &quot;w&quot;, stdout);\r\n#endif\r\n\r\n    DO(RD(n)-1) {\r\n        int x, y, w; RD(x, y, w);\r\n        adj&#x5B;x].PB({y,w});\r\n        adj&#x5B;y].PB({x,w});\r\n    }\r\n\r\n    dfs1(); dfs2();\r\n    cout &lt;&lt; z &lt;&lt; endl;\r\n}\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>https:\/\/www.luogu.com.cn\/problem\/P3647 https:\/\/oj.uz\/problem\/view\/APIO14_beads \u65e0\u6839\u6811\u4e0d\u592a\u597d\u8bbe\u8ba1\u72b6\u6001\uff0c\u60f3\u529e\u6cd5\u8f6c\u6210\u6709\u6839\u6811\uff0c\u7136\u540e\u7528\u5b50\u6811\u66ff\u6362\u5927\u6cd5\u3002 \u518d\u8dd1\u6362\u6839 dp\u3002 \u6211\u6c38\u8fdc\u7231\u5b8f\u3002 #include &lt;lastweapon\/io&gt; using namespace lastweapon; const int N = int(2e5) + 9; int d&#x5B;N]&#x5B;2], e&#x5B;N]&#x5B;2], z; VII adj&#x5B;N]; int n; #define dv (max(d&#x5B;v]&#x5B;0], d&#x5B;v]&#x5B;1] + w)) #define tv ((d&#x5B;v]&#x5B;0] + w) &#8211; dv) #define dp (max(e&#x5B;u]&#x5B;0], e&#x5B;u]&#x5B;1] + pw)) #define tp ((e&#x5B;u]&#x5B;0] + pw) &#8211; dp) void dfs1(int u [&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-2975","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p2tdP7-LZ","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/2975","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=2975"}],"version-history":[{"count":2,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/2975\/revisions"}],"predecessor-version":[{"id":2977,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/2975\/revisions\/2977"}],"wp:attachment":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/media?parent=2975"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/categories?post=2975"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/tags?post=2975"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}