{"id":136,"date":"2023-04-17T20:46:00","date_gmt":"2023-04-17T12:46:00","guid":{"rendered":"https:\/\/solost.cn\/?p=136"},"modified":"2023-04-17T21:39:01","modified_gmt":"2023-04-17T13:39:01","slug":"244","status":"publish","type":"post","link":"https:\/\/solost.cn\/?p=136","title":{"rendered":"Prime"},"content":{"rendered":"

prime<\/h2>\n

\"image.png\"<\/p>\n

\u6a21\u677f<\/h2>\n
\/*\nS:\u5f53\u524d\u5df2\u7ecf\u5728\u8054\u901a\u5757\u4e2d\u7684\u6240\u6709\u70b9\u7684\u96c6\u5408\n1. dist[i] = inf\n2. for n \u6b21\n    t<-S\u5916\u79bbS\u6700\u8fd1\u7684\u70b9\n    \u5229\u7528t\u66f4\u65b0S\u5916\u70b9\u5230S\u7684\u8ddd\u79bb\n    st[t] = true\nn\u6b21\u8fed\u4ee3\u4e4b\u540e\u6240\u6709\u70b9\u90fd\u5df2\u52a0\u5165\u5230S\u4e2d\n\u8054\u7cfb\uff1aDijkstra\u7b97\u6cd5\u662f\u66f4\u65b0\u5230\u8d77\u59cb\u70b9\u7684\u8ddd\u79bb\uff0cPrim\u662f\u66f4\u65b0\u5230\u96c6\u5408S\u7684\u8ddd\u79bb\n*\/\n#include <iostream>\n#include <cstring>\nusing namespace std;\nconst int N = 510, INF = 0x3f3f3f3f;\n\nint n, m;\nint g[N][N], dist[N];\n\/\/\u90bb\u63a5\u77e9\u9635\u5b58\u50a8\u6240\u6709\u8fb9\n\/\/dist\u5b58\u50a8\u5176\u4ed6\u70b9\u5230S\u7684\u8ddd\u79bb\nbool st[N];\n\nint prim() {\n    \/\/\u5982\u679c\u56fe\u4e0d\u8fde\u901a\u8fd4\u56deINF, \u5426\u5219\u8fd4\u56deres\n    memset(dist, INF, sizeof dist);\n    int res = 0;\n\n    for(int i = 0; i < n; i++) {\n        int t = -1;\n        for(int j = 1; j <= n; j++) \n            if(!st[j] && (t == -1 || dist[t] > dist[j]))\n                t = j;\n        \/\/\u5bfb\u627e\u79bb\u96c6\u5408S\u6700\u8fd1\u7684\u70b9  \n        if(i && dist[t] == INF) return INF;\n        \/\/\u5224\u65ad\u662f\u5426\u8fde\u901a\uff0c\u6709\u65e0\u6700\u5c0f\u751f\u6210\u6811\n\n        if(i) res += dist[t];\n        \/\/cout << i << ' ' << res << endl;\n        st[t] = true;\n        \/\/\u66f4\u65b0\u6700\u65b0S\u7684\u6743\u503c\u548c\n\n        for(int j = 1; j <= n; j++) dist[j] = min(dist[j], g[t][j]);\n    }\n\n    return res;\n}\n\nint main() {\n    cin >> n >> m;\n    int u, v, w;\n\n    for(int i = 1; i <= n; i++)\n        for(int j = 1; j <= n; j++)\n            if(i ==j) g[i][j] = 0;\n            else g[i][j] = INF;\n\n    while(m--) {\n        cin >> u >> v >> w;\n        g[u][v] = g[v][u] = min(g[u][v], w);\n    }\n    int t = prim();\n    \/\/\u4e34\u65f6\u5b58\u50a8\u9632\u6b62\u6267\u884c\u4e24\u6b21\u51fd\u6570\u5bfc\u81f4\u6700\u540e\u4ec5\u8fd4\u56de0\n    if(t == INF) puts("impossible");\n    else cout << t << endl;\n}<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
prime \u6a21\u677f \/* S:\u5f53\u524d\u5df2\u7ecf\u5728\u8054\u901a\u5757\u4e2d\u7684\u6240\u6709\u70b9\u7684\u96c6\u5408 1. dist[i] = inf 2. for n \u6b21 t<-S\u5916\u79bbS\u6700\u8fd1\u7684\u70b9 \u5229\u7528t\u66f4\u65b0S\u5916\u70b9\u5230S\u7684\u8ddd\u79bb st[t] = true n\u6b21\u8fed\u4ee3\u4e4b\u540e\u6240\u6709\u70b9\u90fd\u5df2\u52a0\u5165\u5230S\u4e2d \u8054\u7cfb\uff1aDijkstra\u7b97\u6cd5\u662f\u66f4\u65b0\u5230\u8d77\u59cb\u70b9\u7684\u8ddd\u79bb\uff0cPrim\u662f\u66f4\u65b0\u5230\u96c6\u5408S\u7684\u8ddd\u79bb *\/ #include <iostream> #include <cstring> using namespace std; const int N = 510, INF = 0x3f3f3f3f; int n, m; int g[N][N], dist[N]; \/\/\u90bb\u63a5\u77e9\u9635\u5b58\u50a8\u6240\u6709\u8fb9 \/\/dist\u5b58\u50a8\u5176\u4ed6\u70b9\u5230S\u7684\u8ddd\u79bb bool st[N]; int prim() { \/\/\u5982\u679c\u56fe\u4e0d\u8fde\u901a\u8fd4\u56deINF, \u5426\u5219\u8fd4\u56deres memset(dist, INF, sizeof dist); int […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[72],"tags":[51,31,52],"class_list":["post-136","post","type-post","status-publish","format-standard","hentry","category-acm","tag-prime","tag-31","tag-52"],"_links":{"self":[{"href":"https:\/\/solost.cn\/index.php?rest_route=\/wp\/v2\/posts\/136","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/solost.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/solost.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/solost.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/solost.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=136"}],"version-history":[{"count":0,"href":"https:\/\/solost.cn\/index.php?rest_route=\/wp\/v2\/posts\/136\/revisions"}],"wp:attachment":[{"href":"https:\/\/solost.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=136"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/solost.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=136"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/solost.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=136"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}