{"id":624,"date":"2020-06-10T23:04:28","date_gmt":"2020-06-10T15:04:28","guid":{"rendered":"http:\/\/www.guanhaobo.cn\/?p=624"},"modified":"2020-06-10T23:04:28","modified_gmt":"2020-06-10T15:04:28","slug":"bjtuoj-1929-battle","status":"publish","type":"post","link":"https:\/\/www.guanhaobo.cn\/?p=624","title":{"rendered":"BJTUOJ 1929 \u2014 Battle"},"content":{"rendered":"

\u9898\u76ee<\/h3>\n

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\u9898\u76ee\u94fe\u63a5<\/h3>\n

https:\/\/citel.bjtu.edu.cn\/acm\/problem\/1929<\/a><\/p>\n

\u8f93\u5165\u6570\u636e<\/h3>\n

\u7b2c\u4e00\u884c\u4e3a\u4e00\u4e2a\u6574\u6570 n (1\u2264n\u22641000)\uff0c\u8868\u793a\u5076\u50cf\u7684\u4e2a\u6570\u3002
\n\u63a5\u4e0b\u6765 n\u22121 \u884c\uff0c\u7b2c i \u884c\u6709 n\u2212i \u4e2a\u6570\uff0c\u7b2c j \u4e2a\u6570\u8868\u793a f(i,i+j)\uff0c\u5373\u7b2c i \u4f4d\u5076\u50cf\u548c\u7b2c i+j \u4f4d\u5076\u50cf\u8fdb\u884c\u6bd4\u8d5b\u589e\u52a0\u7684\u70ed\u5ea6\u503c (1\u2264f(i,i+j)\u226410^8)\u3002<\/p>\n

\u8f93\u51fa\u6570\u636e<\/h3>\n

\u4e00\u4e2a\u6574\u6570\uff0c\u4e3a\u901a\u8fc7\u4e00\u8def\u9ed1\u7bb1\u9009\u51fa\u51a0\u519b\u7684\u8fc7\u7a0b\u4e2d\u8282\u76ee\u7684\u6700\u5927\u603b\u70ed\u5ea6\u3002<\/p>\n

\u6837\u4f8b\u8f93\u5165<\/h3>\n
5\n7 3 3 3\n9 3 3\n8 12\n3\n<\/code><\/pre>\n
\u6837\u4f8b\u8f93\u51fa<\/h3>\n
36\n<\/code><\/pre>\n
\u6837\u4f8b\u8bf4\u660e<\/h3>\n
\u5bf9\u6218\u5b89\u6392\u53ca\u80dc\u5229\u60c5\u51b5\u5982\u4e0b\uff1a
\n3\u22125\uff0c\u70ed\u5ea6 12\uff0c3\u83b7\u80dc\uff0c
\n1\u22122\uff0c\u70ed\u5ea6 7\uff0c2\u83b7\u80dc\uff0c
\n3\u22124\uff0c\u70ed\u5ea6 8\uff0c3\u83b7\u80dc\uff0c
\n2\u22123\uff0c\u70ed\u5ea6 9\uff0c\u51a0\u519b\u65e0\u8bba\u662f\u8c01\u90fd\u53ef\u4ee5\u3002
\n\u6700\u540e\u603b\u70ed\u5ea6 12+7+8+9=36\u3002
\n\u53ef\u4ee5\u8bc1\u660e\uff0c\u4e0d\u5b58\u5728\u66f4\u4f18\u7684\u5b89\u6392\u65b9\u6848\u3002<\/p>\n
\u95ee\u9898\u5206\u6790<\/h3>\n
\u8fd9\u4e2a\u95ee\u9898\u53ef\u4ee5\u8f6c\u5316\u4e3a\uff1a\u5728 n \u4e2a\u70b9\u7684\u56fe\u4e2d\uff0c\u6bcf\u4e24\u4e2a\u70b9\u4e4b\u95f4\u90fd\u6709\u4e00\u6761\u65e0\u5411\u8fb9\uff0c\u5373\u603b\u8fb9\u6570\u4e3ak = n * (n - 1)<\/code>\uff0c\u6784\u9020\u51fa\u4e00\u4e2a\u6811\uff08\u8fb9\u6570\u4e3an-1\uff09\uff0c\u6c42\u6811\u7684\u8fb9\u957f\u4e4b\u548c\u7684\u6700\u5927\u503c\u3002
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\n\u6211\u8fd9\u91cc\u4f7f\u7528\u7684\u662fKruskal\u7b97\u6cd5\u3002
\n\u8bb0\u5f55\u6240\u6709\u8fb9\u7684\u4fe1\u606f\uff0c\u5bf9\u8fb9\u6309\u7167\u957f\u5ea6\u4ece\u5927\u5230\u5c0f\u6392\u5e8f\u3002\u7136\u540e\u679a\u4e3e\u6bcf\u4e00\u6761\u8fb9\uff0c\u5982\u679c\u8fd9\u6761\u8fb9\u52a0\u5165\u5b50\u56fe\u4f1a\u4ea7\u751f\u73af\u5219\u629b\u5f03\u8fd9\u6761\u8fb9\uff0c\u53cd\u4e4b\u5219\u5c06\u5176\u52a0\u5165\u5b50\u56fe\u3002
\n\u5982\u4f55\u53bb\u7ef4\u62a4\u5b50\u56fe\u5462\uff1f\u6216\u8005\u8bf4\u5982\u4f55\u5224\u65ad\u6709\u6ca1\u6709\u751f\u6210\u73af\uff1f
\n\u4f7f\u7528\u5e76\u67e5\u96c6\u5c31ok\u4e86\u3002\u5bf9\u4e8e\u4e00\u6761\u8fb9\uff0c\u5224\u65ad\u5b83\u4e24\u4e2a\u9876\u70b9\u7684root\u662f\u5426\u76f8\u540c\uff0c\u5982\u679c\u76f8\u540c\u5219\u8bf4\u660e\u4f1a\u4ea7\u751f\u73af\u3002\u5982\u679c\u4e0d\u76f8\u540c\uff0c\u5c31\u628a\u5b83\u7684\u4e24\u4e2a\u9876\u70b9merge\u4e00\u4e0b\uff0c\u76f8\u5f53\u4e8e\u6dfb\u52a0\u5230\u5b50\u56fe\u3002<\/p>\n
AC\u4ee3\u7801<\/h3>\n
#include <bits\/stdc++.h>\nusing namespace std;\nconst int MAXN = 1005;\nint f[MAXN][MAXN];\nstruct edge\n{\n    int from, to, len;\n    edge(int from1, int to1, int len1) : from(from1), to(to1), len(len1)\n    {\n    }\n    edge()\n    {\n    }\n    bool operator<(const edge &s2)\n    {\n        return len > s2.len;\n    }\n} e[1000005];\nint i, n, ufs[MAXN];\n\nvoid Init()\n{\n    for (i = 0; i < MAXN; i++)\n    {\n        ufs[i] = i;\n    }\n}\nint getroot(int n)\n{\n    if (ufs[n] != n)\n        ufs[n] = getroot(ufs[n]);\n    return ufs[n];\n}\nvoid merge(int a, int b)\n{\n    int x = getroot(a), y = getroot(b);\n    if (x != y)\n        ufs[x] = y;\n}\nint main()\n{\n    Init();\n    int j, k, len, sum = 0, a, b, minnum = 0, NumOfEdge = 0;\n    long long ans = 0;\n    scanf(\"%d\", &n); \/\/n\u4e2a\u70b9k\u6761\u8fb9\n    k = n * (n - 1);\n    for (i = 1; i <= n; i++)\n    {\n        for (j = 1; j <= n - i; j++)\n        {\n            scanf(\"%d\", &f[i][i + j]);\n            e[NumOfEdge++] = edge(i, i + j, f[i][i + j]);\n        }\n    }\n    sort(e, e + NumOfEdge);\n    for (i = 0; i < NumOfEdge; i++)\n    {\n        a = e[i].from, b = e[i].to;\n        if (getroot(a) != getroot(b))\n        {\n            merge(a, b);\n            ans += e[i].len;\n        }\n    }\n    printf(\"%lld\\n\", ans);\n    return 0;\n}\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
\u9898\u76ee \u80af\u5343\u7f51\u7edc\u516c\u53f8\u6700\u65b0\u63a8\u51fa\u4e86\u5b8c\u5168\u7531\u5076\u50cf\u4e00\u5bf9\u4e00\u5bf9\u6218\u6784\u6210\u7684\u7f51\u7edc\u9009\u79c0\u8282\u76ee\u3002\u5728\u8be5\u8282\u76ee\u4e2d\uff0c\u8282\u76ee\u7ec4\u9080\u8bf7\u4e86 n \u4f4d\u5076\u50cf\uff0c\u6bcf\u5929 […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[7,19,43,48],"class_list":["post-624","post","type-post","status-publish","format-standard","hentry","category-algo","tag-bjtuoj","tag-kruskal","tag-43","tag-48"],"_links":{"self":[{"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/posts\/624","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=624"}],"version-history":[{"count":0,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=\/wp\/v2\/posts\/624\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=624"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=624"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.guanhaobo.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=624"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}