{"id":1794,"date":"2021-10-21T12:10:56","date_gmt":"2021-10-21T04:10:56","guid":{"rendered":"http:\/\/www.shuizilong.com\/house\/?p=1794"},"modified":"2023-05-29T20:45:12","modified_gmt":"2023-05-29T12:45:12","slug":"facebook-hacker-cup-2021-round-2","status":"publish","type":"post","link":"https:\/\/www.shuizilong.com\/house\/archives\/facebook-hacker-cup-2021-round-2\/","title":{"rendered":"Facebook Hacker Cup 2021 Round 2"},"content":{"rendered":"<h2>Problem A.<\/h2>\n<p>\u8d2a\u5fc3<\/p>\n<h2>Problem B.<\/h2>\n<p>\u505a\u6cd5\u6709\u5f88\u591a\uff0c\u6bd4\u8d5b\u65f6\u7528\u7684\u662f\u7ebf\u6bb5\u6811\u5408\u5e76\u3002<\/p>\n<h2>Problem C.<\/h2>\n<p>\u5c0f\u6570\u636e\u8d2a\u5fc3\u6a21\u62df\u4e00\u4e0b\uff0c\u5927\u6570\u636e\u9700\u8981\u7528\u6570\u636e\u7ed3\u6784\u7ef4\u62a4\u8fd9\u4e2a\u8d2a\u5fc3\u8fc7\u7a0b\u3002<\/p>\n<h2>Problem D. String Concatenation<\/h2>\n<p>\u867d\u7136\u9898\u76ee\u53eb String Concatenation\uff0c\u4f46\u662f\u662f\u4e2a\u80cc\u5305\u95ee\u9898\uff0c\u548c\u5b57\u7b26\u4e32\u5b8c\u5168\u6728\u6709\u5173\u7cfb\u3002<br \/>\n\u505a\u6cd5\u662f\u66b4\u529b\u4e71\u641e\uff0c\u4e71\u641e\u7684\u65b9\u6cd5\u8c8c\u4f3c\u6709\u5f88\u591a\u3002\u5047\u8bbe k \u53ef\u4ee5\u65e0\u7a77\u5927\uff0c\u90a3\u4e48\u6839\u636e\u9e3d\u5de2\u539f\u7406\uff08pigeonhole principle\uff09\uff0c\u5728 n >= 25 \u7684\u65f6\u5019\u5c31\u4e00\u5b9a\u6709\u89e3\uff0c\u8003\u8651 k \u5f88\u5c0f\uff0c\u90a3\u4e48\u4e5f\u53ef\u4ee5\u6839\u636e\u751f\u65e5\u6096\u8bba\uff08birthday paradox\uff09\u53ef\u4ee5\u8bbe\u8ba1 n &lt;= 1000 \u7684\u89e3\u6cd5\u3002<br \/>\n\u7136\u540e\u4e00\u822c\u60c5\u51b5\u4e0b\u518d\u641e\u4e00\u4e9b\u526a\u679d\uff0c\u5f52\u7ea6\u5230 n &lt;= 1000 \u4ee5\u5185\u5373\u53ef\u3002\u8fd9\u79cd\u5229\u7528\u751f\u65e5\u6096\u8bba\u7684\u9898\u597d\u50cf\u4ee5\u524d gcj \u559c\u6b22\u51fa\u3002\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Problem A. \u8d2a\u5fc3 Problem B. \u505a\u6cd5\u6709\u5f88\u591a\uff0c\u6bd4\u8d5b\u65f6\u7528\u7684\u662f\u7ebf\u6bb5\u6811\u5408\u5e76\u3002 Problem C. \u5c0f\u6570\u636e\u8d2a\u5fc3\u6a21\u62df\u4e00\u4e0b\uff0c\u5927\u6570\u636e\u9700\u8981\u7528\u6570\u636e\u7ed3\u6784\u7ef4\u62a4\u8fd9\u4e2a\u8d2a\u5fc3\u8fc7\u7a0b\u3002 Problem D. String Concatenation \u867d\u7136\u9898\u76ee\u53eb String Concatenation\uff0c\u4f46\u662f\u662f\u4e2a\u80cc\u5305\u95ee\u9898\uff0c\u548c\u5b57\u7b26\u4e32\u5b8c\u5168\u6728\u6709\u5173\u7cfb\u3002 \u505a\u6cd5\u662f\u66b4\u529b\u4e71\u641e\uff0c\u4e71\u641e\u7684\u65b9\u6cd5\u8c8c\u4f3c\u6709\u5f88\u591a\u3002\u5047\u8bbe k \u53ef\u4ee5\u65e0\u7a77\u5927\uff0c\u90a3\u4e48\u6839\u636e\u9e3d\u5de2\u539f\u7406\uff08pigeonhole principle\uff09\uff0c\u5728 n >= 25 \u7684\u65f6\u5019\u5c31\u4e00\u5b9a\u6709\u89e3\uff0c\u8003\u8651 k \u5f88\u5c0f\uff0c\u90a3\u4e48\u4e5f\u53ef\u4ee5\u6839\u636e\u751f\u65e5\u6096\u8bba\uff08birthday paradox\uff09\u53ef\u4ee5\u8bbe\u8ba1 n &lt;= 1000 \u7684\u89e3\u6cd5\u3002 \u7136\u540e\u4e00\u822c\u60c5\u51b5\u4e0b\u518d\u641e\u4e00\u4e9b\u526a\u679d\uff0c\u5f52\u7ea6\u5230 n &lt;= 1000 \u4ee5\u5185\u5373\u53ef\u3002\u8fd9\u79cd\u5229\u7528\u751f\u65e5\u6096\u8bba\u7684\u9898\u597d\u50cf\u4ee5\u524d gcj \u559c\u6b22\u51fa\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":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false}}},"categories":[1],"tags":[],"class_list":["post-1794","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p2tdP7-sW","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/1794","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=1794"}],"version-history":[{"count":2,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/1794\/revisions"}],"predecessor-version":[{"id":2941,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/1794\/revisions\/2941"}],"wp:attachment":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/media?parent=1794"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/categories?post=1794"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/tags?post=1794"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}