{"id":1096,"date":"2025-06-01T13:30:00","date_gmt":"2025-06-01T05:30:00","guid":{"rendered":"https:\/\/seanxd.com\/?p=1096"},"modified":"2025-05-30T19:25:00","modified_gmt":"2025-05-30T11:25:00","slug":"zerojudge-d831","status":"publish","type":"post","link":"https:\/\/seanxd.com\/en\/zerojudge-d831\/","title":{"rendered":"ZeroJudge D831: Graduation Trip"},"content":{"rendered":"\n\n\n

\u591a\u5e74\u4f86\u53cb\u60c5\u7684\u7f88\u7d46\uff0c\u7d42\u65bc\u5c07\u5728\u9019\u7562\u696d\u7684\u5b63\u7bc0\u958b\u82b1\u7d50\u679c\u3002<\/p>\n\n\n\n

\u9019\u5e7e\u5929\uff0c\u73ed\u4e0a\u540c\u5b78\u5011\u7121\u6642\u7121\u523b\u90fd\u71b1\u70c8\u8a0e\u8ad6\u8457\u7562\u696d\u65c5\u884c\u7684\u5730\u9ede\u3002<\/p>\n\n\n\n

\u5c0f\u660e\u8aaa\uff0c\u5982\u679c\u8981\u53bb\u516d\u798f\u6751\uff0c\u53ef\u4ee5\u9806\u4fbf\u53bb\u5c0f\u4eba\u570b\uff1b<\/p>\n\n\n\n

\u5c0f\u7f8e\u8aaa\uff0c\u5982\u679c\u53bb\u4e86\u6046\u6625\u7684\u8a71\uff0c\u58be\u4e01\u5c31\u5728\u5e7e\u5341\u516c\u91cc\u5916\u4e86\uff0c\u4e00\u5b9a\u4e5f\u8981\u53bb\u73a9\uff1b<\/p>\n\n\n\n

\u5c0f\u83ef\u8868\u793a\uff0c\u5c0f\u9b3c\u6e56\u8ddf\u5927\u9b3c\u6e56\u597d\u50cf\u5f88\u8fd1\uff0c\u4f3c\u4e4e\u90fd\u662f\u5f88\u6709\u8da3\u7684\u5730\u65b9\u3002<\/p>\n\n\n\n

\u8eab\u70ba\u73ed\u9577\uff0c\u807d\u5230\u540c\u5b78\u9019\u9ebc\u591a\u300c\u53bb\u4e86\u54ea\u88e1\u4e5f\u53ef\u4ee5\u53bb\u54ea\u88e1\u300d\u7684\u8cc7\u8a0a\u5f8c\uff0c\u4f60\u6c7a\u5b9a\u8981\u70ba\u73ed\u4e0a\u7684\u540c\u5b78\u5011\uff0c\u627e\u5230\u4e00\u500b\u80fd\u73a9\u6700\u591a\u666f\u9ede\u7684\u7562\u696d\u65c5\u884c\u3002<\/p>\n\n\n\n

\u7bc4\u4f8b\u6e2c\u8cc7<\/h2>\n\n\n\n
\u7bc4\u4f8b\u8f38\u5165<\/th>\u7bc4\u4f8b\u8f38\u51fa<\/th><\/tr><\/thead>
\u6709\u591a\u7d44\u6e2c\u8a66\u8cc7\u6599\uff0c\u4ee5 EOF \u7d50\u675f\u3002
\u6bcf\u7d44\u6e2c\u8a66\u8cc7\u6599\u7684\u7b2c\u4e00\u884c\u6709\u5169\u500b\u6b63\u6574\u6578 N (N <= 1000000) \u548c M (M <= 100000)\uff0c\u8868\u793a\u666f\u9ede\u6709 N \u500b\uff0c\u7de8\u865f\u70ba 0\uff5eN-1\u3002
\u63a5\u4e0b\u4f86\u6709 M \u884c\uff0c\u6bcf\u884c\u6709\u5169\u500b\u6574\u6578 a \u548c b (0 <= a\u3001b < N)\uff0c\u8868\u793a\u53bb\u4e86 a \u7684\u540c\u6642\u4e5f\u53ef\u4ee5\u53bb b (\u53cd\u904e\u4f86\u4e5f\u4e00\u6a23\uff09\u3002<\/td>		\u8f38\u51fa\u4e00\u500b\u6578\u5b57\uff0c\u8868\u793a\u7562\u696d\u65c5\u884c\u6700\u591a\u53ef\u4ee5\u73a9\u7684\u666f\u9ede\u6578\u91cf\u3002<\/td><\/tr>
6 4
0 1
2 3
1 3
5 4
1000000 0
1000000 1
0 999999<\/td>		4
1
2<\/td><\/tr><\/tbody><\/table>
ZeroJudge D831 \u7bc4\u4f8b\u6e2c\u8cc7<\/figcaption><\/figure>\n\n\n\n

\u89e3\u984c\u601d\u8def<\/h2>\n\n\n\n

\u4f7f\u7528 Map \u4f86\u7d00\u9304\u6bcf\u4e00\u500b\u666f\u9ede\u7684\u6700\u5e95\u5c64\uff0c\u6240\u6709\u9810\u8a2d\u503c\u70ba -1\u3002<\/p>\n\n\n\n

\u5ba3\u544a\u4e00\u500b\u51fd\u5f0f findEnd\uff0c\u9700\u8981\u4e00\u500b\u53c3\u6578 N\uff0c\u5982\u679c N == -1 || Map[N] == -1\uff0creturn N\u3002\u5982\u679c Map[N] == N\uff0creturn N\u3002\u5426\u5247 return findEnd(Map[N])\u3002<\/p>\n\n\n\n

\u8f38\u5165\u8cc7\u6599\u6642\uff0c\u5982\u679c\u5169\u500b\u90fd\u6c92\u6709\u7d00\u9304\uff0c\u5247\u5c07\u53f3\u908a\u7684\u8a2d\u5b9a\u70ba\u5de6\u908a\u7684\u3002\u5982\u679c\u5169\u500b\u4eba\u90fd\u6709\u7d00\u9304\uff0c\u5c07\u5176\u4e2d\u4e00\u500b\u7684 Map \u503c\u8a2d\u70ba findEnd(\u53e6\u4e00\u500b\u4eba)\u3002\u5982\u679c\u662f\u4e00\u500b\u6709\u4e00\u500b\u6c92\u6709\uff0c\u5247\u5c07\u6c92\u6709\u7684\u4eba\u7684 Map \u503c\u8a2d\u5b9a\u6210 findEnd(\u53e6\u4e00\u500b\u4eba)\u3002<\/p>\n\n\n\n

\u6536\u5b8c\u8cc7\u6599\u4e4b\u5f8c\u5ba3\u544a\u4e00\u500b map<int, int>ans\uff0c\u4ee3\u8868\u8981\u7d00\u9304\u7684\u6700\u591a\u666f\u9ede\u6578\u3002\u8dd1\u4e00\u500b\u5f9e 0 \u5230 N-1 \u7684\u8ff4\u5708\uff0c\u5982\u679c findEnd(\u76ee\u524d\u6578\u5b57) != -1\uff0c\u5247\u5c07 ans[findEnd(\u76ee\u524d\u6578\u5b57)]++\uff0c\u4e26\u4e14\u5224\u65b7\u6700\u5927\u503c\u3002\u7b54\u6848\u5c31\u662f\u6700\u5927\u503c\u3002<\/p>\n\n\n\n

\u7bc4\u4f8b\u7a0b\u5f0f\u78bc\uff0dZeroJudge D831: \u7562\u696d\u65c5\u884c<\/a><\/h3>\n\n\n\n
#include <iostream>\n#include <map>\nusing namespace std;\n\nint N, M;\nmap<int, int>MAP;\n\nint findEnd(const int N) {\n    if (N == -1 || MAP[N] == -1) return -1;\n    if (MAP[N] == N) return N;\n    return findEnd(MAP[N]);\n}\n\nvoid graduate(const int a, const int b) {\n    if (MAP[a] == -1 && MAP[b] == -1) {\n        if (b == 0) {\n            MAP[a] = b;\n            MAP[b] = b;\n        }\n        else {\n            MAP[a] = a;\n            MAP[b] = a;\n        }\n    }\n    else if (MAP[a] != -1 && MAP[b] != -1) {\n        if (findEnd(MAP[b]) == 0) MAP[findEnd(a)] = 0;\n        else MAP[findEnd(b)] = findEnd(a);\n    }\n    else {\n        if (MAP[a] != -1) MAP[b] = findEnd(a);\n        else MAP[a] = findEnd(b);\n    }\n}\n\nint main() {\n    cin.sync_with_stdio(0);\n    cin.tie(0);\n    while (cin >> N >> M) {\n        if (M == 0) {\n            cout << "1\\n";\n            continue;\n        }\n        MAP.clear();\n        for (int i = 0; i<N; i++) MAP[i] = -1;\n        for (int i = 0; i<M; i++) {\n            int a, b;\n            cin >> a >> b;\n            graduate(a, b);\n        }\n        map<int, int>ans;\n        int max = -999;\n        for (int i = 0; i<N; i++) {\n            const int tmp = findEnd(i);\n            if (tmp != -1) ans[tmp]++;\n            if (ans[tmp] > max) max = ans[tmp];\n        }\n        cout << max << "\\n";\n    }\n}\n\n\/\/ZeroJudge D831\n\/\/Dr. SeanXD<\/code><\/pre><\/div>\n\n\n\n
\u6211\u7684\u5b87\u6046\uff0c\u7562\u696d\u5feb\u6a02\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
\u591a\u5e74\u4f86\u53cb\u60c5\u7684\u7f88\u7d46\uff0c\u7d42\u65bc\u5c07\u5728\u9019\u7562\u696d\u7684\u5b63\u7bc0\u958b\u82b1\u7d50\u679c\u3002 \u9019\u5e7e\u5929\uff0c\u73ed\u4e0a\u540c\u5b78\u5011\u7121\u6642\u7121\u523b\u90fd\u71b1\u70c8\u8a0e\u8ad6\u8457\u7562\u696d\u65c5\u884c\u7684\u5730\u9ede\u3002 \u5c0f\u660e […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"nf_dc_page":"","footnotes":""},"categories":[29],"tags":[14,8,9],"class_list":["post-1096","post","type-post","status-publish","format-standard","hentry","category-zerojudge-","tag-map","tag-8","tag-9"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/seanxd.com\/en\/wp-json\/wp\/v2\/posts\/1096","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/seanxd.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/seanxd.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/seanxd.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/seanxd.com\/en\/wp-json\/wp\/v2\/comments?post=1096"}],"version-history":[{"count":6,"href":"https:\/\/seanxd.com\/en\/wp-json\/wp\/v2\/posts\/1096\/revisions"}],"predecessor-version":[{"id":1337,"href":"https:\/\/seanxd.com\/en\/wp-json\/wp\/v2\/posts\/1096\/revisions\/1337"}],"wp:attachment":[{"href":"https:\/\/seanxd.com\/en\/wp-json\/wp\/v2\/media?parent=1096"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/seanxd.com\/en\/wp-json\/wp\/v2\/categories?post=1096"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/seanxd.com\/en\/wp-json\/wp\/v2\/tags?post=1096"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}