{"id":277,"date":"2012-06-30T17:32:31","date_gmt":"2012-06-30T09:32:31","guid":{"rendered":"http:\/\/www.shuizilong.com\/house\/?p=277"},"modified":"2012-07-14T04:14:50","modified_gmt":"2012-07-13T20:14:50","slug":"codeforces-round-127","status":"publish","type":"post","link":"https:\/\/www.shuizilong.com\/house\/archives\/codeforces-round-127\/","title":{"rendered":"Codeforces Round #127"},"content":{"rendered":"

Brief description: <\/h3>\n

Problem A. Clear Symmetry
\n\u3002\u3002\u4e00\u4e2a 01 \u77e9\u9635\u88ab\u79f0\u4e4b\u4e3a\uff1a
\nClear: \u5982\u679c\u6ca1\u6709 1 \u76f8\u90bb\u3002
\nSymmetrical: \u5982\u679c\u5728 \u65cb\u8f6c90\u5ea6 \u7684\u4f5c\u7528\u4e0b\u4e0d\u53d8\u3002
\n\u8981\u6c42\u5728\u6ee1\u8db3\u4e0a\u8ff0\u6027\u8d28\u7684\u60c5\u51b5\u4e0b\uff0c\u6784\u9020\u4e00\u4e2a\u9636\u6570\u6700\u5c11\u7684\u6709 x \u4e2a 1 \u7684 01 \u77e9\u9635\uff0c\u6c42\u8fd9\u4e2a\u9636\u6570\u3002<\/p>\n

Problem B. Guess That Car!
\n\u7ed9\u5b9a\u4e00\u4e2a N\u00d7M \u7684\u683c\u70b9\uff0c\u6bcf\u4e2a\u70b9\u6709\u4e00\u4e2a\u5168\u503c Aij\uff0c\u5f53\u4eba\u7ad9\u5728\u67d0\u4e2a\u4ea4\u70b9\u4f4d\u7f6e\u65f6\u5c06\u5bf9\u6bcf\u4e2a\u683c\u70b9\u4ea7\u751f\u4e00\u4e2a\u4ee3\u4ef7\u3002
\n\u5b9a\u4e49\u4e3a Aij \u4e58\u4ee5\u8ddd\u79bb\u7684\u5e73\u65b9\u3002\u95ee\u7ad9\u5728\u54ea\u4e2a\u4f4d\u7f6e\u65f6\uff0c\u6240\u6709\u683c\u5b50\u4ea7\u751f\u7684\u4ee3\u4ef7\u6700\u5c11\u3002<\/p>\n

Problem C. Fragile Bridges
\n\u7ed9\u5b9a\u4e00\u6392\u8981\u77f3\uff0c\u8981\u77f3\u4e0e\u8981\u77f3\u4e4b\u95f4\u6709\u4e00\u5ea7\u6865\uff0c\u6bcf\u4e2a\u6865\u6709\u4e00\u4e2a\u8010\u4e45\u5ea6 Ai\uff0c\u5f53\u5f80\u5230\u8fbe Ai \u6b21\u7684\u65f6\u5019\uff0c
\n\u6865\u4f1a\u574d\u584c\uff0c\u95ee\u80fd\u79fb\u52a8\u7684\u6700\u957f\u6b65\u6570\u3002\uff08\u53ef\u4ece\u4efb\u610f\u4f4d\u7f6e\u5f00\u59cb\u3002\u3002<\/p>\n

Problem D. Brand New Problem
\n\u7ed9\u5b9a n \u548c\u4e00\u4e2a\u957f\u5ea6\u4e3a l \u7684\u6570\u7ec4\uff0c\u6784\u9020\u4e00\u4e2a\u5927\u5c0f\u4e3a n \u7684\u5b50\u5e8f\u5217\uff0c\u4f7f\u5f97\u5176\u6784\u6210 1, n \u7684\u4e00\u4e2a\u91cd\u6392\uff0c\u4e14\u9006\u5e8f\u6570\u5c3d\u53ef\u80fd\u5c0f\u3002
\n\uff08 n \u2264 15, l \u2264 500000 .. .)<\/p>\n

Problem E. Thoroughly Bureaucratic Organization
\n\u5df2\u77e5\u6709\u4e00\u4e2a\u957f\u5ea6\u4e3a n \u6392\u5217\uff0c\u4f46\u4e0d\u77e5\u9053\u6bcf\u4e2a\u4f4d\u7f6e\u5206\u522b\u662f\u591a\u5c11\uff0c\u6bcf\u6b21\u8be2\u95ee\u53ef\u4ee5\u786e\u5b9a\u5176\u4e2d\u81f3\u591a m \u4e2a\u69fd\u4f4d\u6709\u54ea\u4e9b\u6570\u3002\u3002
\n\uff08\u4f46\u4e0d\u80fd\u786e\u5b9a\u5177\u4f53\u7684\u4f4d\u7f6e\uff09\u3002\u3002\u95ee\u6700\u5c11\u591a\u5c11\u6b21\u8be2\u95ee\u53ef\u4ee5\u8fd8\u539f\u4e4b\u3002\u3002\u3002<\/p>\n

<\/p>\n

Analysis: <\/h3>\n

Problem A. Clear Symmetry
\n\u3002\u3002\u3002\u9996\u5148\u89c2\u5bdf\u6ce8\u610f\u5230\u5076\u6570\u60c5\u51b5\u4e0b bug \uff08\u8fd8\u6ca1\u6709\u8f83\u5c0f\u4e00\u9636\u7684\u5947\u6570\u4f18\u3002\u3002
\n…\u7136\u540e\u5236\u4f5c int r(x); \u8868\u793a\u9636\u6570\u4e3a x \u7684\u65f6\u5019\u6700\u591a\u80fd\u4ea7\u751f\u591a\u5c11\u4e2a 1 \u3002
\n\u3002\u3002\u3002\u7136\u540e\u7a0d\u5fae\u6784\u9020\u4e00\u4e0b\u53d1\u73b0\u6bd4\u8fd9\u4e2a\u6570\u5c0f\u60c5\u51b5\u90fd\u662f\u53ef\u4ee5\u6784\u9020\u51fa\u6765\u7684\u3002\u3002\uff08\u9664\u4e86 3 \u9636\uff0c\u7279\u5224\u4e00\u4e0b\u5c31\u4ea4\u4e86\u3002\u3002<\/p>\n

Problem B. Guess That Car!
\n\u8003\u8651\u5230\u516c\u5f0f\u662f\u53ef\u4ee5\u5bf9 x \u8f74\u548c y \u8f74\u5206\u79bb\u7684\u3002\u3002\u4e8e\u662f O(n) \u62d6\u51fa\u6765\u505a\u4e24\u6b21\u9884\u5904\u7406\u5373\u53ef\u3002\u3002<\/p>\n

Problem C. Fragile Bridges
\n\u3002\u3002SB \u52a8\u6001\u89c4\u5212\uff0c\u5b9a\u4e49\u5de6\u53f3\u4e24\u8fb9\u4ee5\u53ca\u80fd\u5426\u8fd4\u56de\u56db\u4e2a\u72b6\u6001\u3002\u3002\u3002
\n\uff08\u53c2\u89c1\u3002\u3002\u3002http:\/\/acm.uestc.edu.cn\/problem.php?pid=1649
\n<\/a><\/p>\n

Problem D. Brand New Problem
\n\u5b9a\u4e49 dp[s][i] \u8868\u793a\u4f7f\u7528\u7684\u6570\u5b57\u96c6\u5408\u4e3a s, \u9006\u5e8f\u6570\u4e3a i \u65f6\uff0c\u5728\u6587\u672c\u4e2d\u6240\u5904\u7684\u4f4d\u7f6e\u3002\u3002\uff08\u3002\u6700\u5de6\u8fb9\u90a3\u4e2a\u3002\u3002
\n\u3002\u7136\u540e\u5236\u4f5c\u8f85\u52a9\u6570\u7ec4 p[i]][j] \u8868\u793a\u7b2c i \u4e2a\u4f4d\u7f6e\u5f00\u59cb\u51fa\u73b0 j \u7684\u6700\u9760\u5de6\u7684\u4f4d\u7f6e\u3002\u3002\u5c31\u80fd\u8f6c\u79fb\u4e86\u3002\u3002\u256e(\u256f_\u2570)\u256d<\/p>\n

Problem E. Thoroughly Bureaucratic Organization
\n\u5bf9\u4e8e\u4efb\u610f\u4e24\u4e2a\u6570 i, j\uff0c \u4e3a\u4e86\u533a\u5206\u4e24\u4e2a\u6570\u5b57\u7684\u4f4d\u7f6e\u3002\u3002
\n\u5219\u81f3\u5c11\u5b58\u5728\u4e00\u7ec4\u8be2\u95ee\u53ea\u5305\u542b i \u6216\u53ea\u5305\u542b j \u3002\u3002\u3002\u3002<\/p>\n

\u4e8e\u662f\u95ee\u9898\u7b49\u4ef7\u4e8e SRM 484 \u7684 1000<\/a> \u3002\u3002\u3002<\/p>\n

\uff08\u5bf9\u4e8e\u6bcf\u6b21\u4e0d\u5fc5\u7528\u586b\u6ee1 m \u4e2a\u6570\u7684\u95ee\u9898\u3002\u3002\u53d1\u73b0\u5bf9\u95ee\u9898\u4e0d\u6784\u6210\u592a\u5927\u5f71\u54cd\u3002\u53ea\u662f\u518d m > n \/ 2 \u65f6\uff0c\u53d6 m = n \/ 2 \u5373\u53ef\u3002\u3002\u3002<\/p>\n

Code: <\/h3>\n

A<\/a> B<\/a> C<\/a> D<\/a> E<\/a><\/p>\n

External link: <\/h3>\n

http:\/\/codeforces.com\/contest\/201\/room\/5<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Brief description: Problem A. Clear Symmetry \u3002\u3002\u4e00\u4e2a 01 \u77e9\u9635\u88ab\u79f0\u4e4b\u4e3a\uff1a Clear: \u5982\u679c\u6ca1\u6709 1 \u76f8\u90bb\u3002 Symmetrical: \u5982\u679c\u5728 \u65cb\u8f6c90\u5ea6 \u7684\u4f5c\u7528\u4e0b\u4e0d\u53d8\u3002 \u8981\u6c42\u5728\u6ee1\u8db3\u4e0a\u8ff0\u6027\u8d28\u7684\u60c5\u51b5\u4e0b\uff0c\u6784\u9020\u4e00\u4e2a\u9636\u6570\u6700\u5c11\u7684\u6709 x \u4e2a 1 \u7684 01 \u77e9\u9635\uff0c\u6c42\u8fd9\u4e2a\u9636\u6570\u3002 Problem B. Guess That Car! \u7ed9\u5b9a\u4e00\u4e2a N\u00d7M \u7684\u683c\u70b9\uff0c\u6bcf\u4e2a\u70b9\u6709\u4e00\u4e2a\u5168\u503c Aij\uff0c\u5f53\u4eba\u7ad9\u5728\u67d0\u4e2a\u4ea4\u70b9\u4f4d\u7f6e\u65f6\u5c06\u5bf9\u6bcf\u4e2a\u683c\u70b9\u4ea7\u751f\u4e00\u4e2a\u4ee3\u4ef7\u3002 \u5b9a\u4e49\u4e3a Aij \u4e58\u4ee5\u8ddd\u79bb\u7684\u5e73\u65b9\u3002\u95ee\u7ad9\u5728\u54ea\u4e2a\u4f4d\u7f6e\u65f6\uff0c\u6240\u6709\u683c\u5b50\u4ea7\u751f\u7684\u4ee3\u4ef7\u6700\u5c11\u3002 Problem C. Fragile Bridges \u7ed9\u5b9a\u4e00\u6392\u8981\u77f3\uff0c\u8981\u77f3\u4e0e\u8981\u77f3\u4e4b\u95f4\u6709\u4e00\u5ea7\u6865\uff0c\u6bcf\u4e2a\u6865\u6709\u4e00\u4e2a\u8010\u4e45\u5ea6 Ai\uff0c\u5f53\u5f80\u5230\u8fbe Ai \u6b21\u7684\u65f6\u5019\uff0c \u6865\u4f1a\u574d\u584c\uff0c\u95ee\u80fd\u79fb\u52a8\u7684\u6700\u957f\u6b65\u6570\u3002\uff08\u53ef\u4ece\u4efb\u610f\u4f4d\u7f6e\u5f00\u59cb\u3002\u3002 Problem D. Brand New Problem \u7ed9\u5b9a n \u548c\u4e00\u4e2a\u957f\u5ea6\u4e3a l \u7684\u6570\u7ec4\uff0c\u6784\u9020\u4e00\u4e2a\u5927\u5c0f\u4e3a […]<\/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":[18],"tags":[],"class_list":["post-277","post","type-post","status-publish","format-standard","hentry","category-codeforces"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p2tdP7-4t","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/277","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=277"}],"version-history":[{"count":1,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/277\/revisions"}],"predecessor-version":[{"id":278,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/posts\/277\/revisions\/278"}],"wp:attachment":[{"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/media?parent=277"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/categories?post=277"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.shuizilong.com\/house\/wp-json\/wp\/v2\/tags?post=277"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}