{"id":481,"date":"2019-08-12T20:05:34","date_gmt":"2019-08-12T12:05:34","guid":{"rendered":"http:\/\/47.101.202.111\/?p=481"},"modified":"2023-04-07T16:16:39","modified_gmt":"2023-04-07T08:16:39","slug":"%e7%ae%97%e6%b3%95%e4%b8%b2%e7%9a%84%e6%a8%a1%e5%bc%8f%e5%8c%b9%e9%85%8d","status":"publish","type":"post","link":"http:\/\/139.196.114.170\/?p=481","title":{"rendered":"\u4e32\u7684\u6a21\u5f0f\u5339\u914d – \u8d85\u8d8a\u7ebf\u6027\u65f6\u95f4\u5bfb\u627e\u5b50\u4e32"},"content":{"rendered":"

\u66b4\u529b\u5339\u914d<\/h2>\n

\u6a21\u5f0f\u4e32\u4ece\u5934\u5230\u5c3e\u63a8\u8fdb\uff0c\u5339\u914d\u65f6\u4ece\u5de6\u5411\u53f3\u5339\u914d\uff0c\u5339\u914d\u5931\u8d25\u65f6\u5411\u524d\u63a8\u8fdb\u4e00\u4e2a\u5b57\u7b26<\/p>\n

int BrutalForce(string p, string s)\n{\n    int M = p.length();\n    int N = s.length();\n    for (int i = 0; i <= N - M; i++)\n    {\n        int j;\n        for (j = 0; j < M; j++)\n            if (s[i + j] != p[j])\n                break;\n        if (j == M) return i;\n    }\n    return N;\n}<\/code><\/pre>\n
KMP\u7b97\u6cd5<\/h2>\n
\u6a21\u5f0f\u4e32\u4ece\u5934\u5230\u5c3e\u63a8\u8fdb\uff0c\u5339\u914d\u65f6\u4ece\u5de6\u5411\u53f3\u5339\u914d\uff0c\u5339\u914d\u5931\u8d25\u65f6\u8df3\u6b65\uff0c\u53ef\u8fbeO(N+M)<\/p>\n
\u66b4\u529b\u5339\u914d\u5931\u8d25\u65f6\u4f1a\u5c06\u6307\u9488\u56de\u9000\u5230\u6a21\u5f0f\u4e32\u521d\u59cb\u4f4d\u7f6e\uff0cKMP\u7b97\u6cd5\u4f9d\u636e\u5df2\u5339\u914d\u90e8\u5206\u8fdb\u884c\u8df3\u6b65\u907f\u514d\u6307\u9488\u56de\u9000<\/p>\n
\u5339\u914d\u8fdb\u884c\u5230\u5931\u8d25\u5b57\u7b26fail\u65f6\uff0c\u82e5fail\u5728\u6a21\u5f0f\u4e32\u4e2d\uff0c\u5219\u5c06fail\u5bf9\u51c6<\/p>\n
\u82e5fail\u4e0d\u5728\u6a21\u5f0f\u4e32\u4e2d\uff0c\u542b\u6709fail\u7684\u5b50\u4e32\u5747\u65e0\u6cd5\u5339\u914d\uff0c\u76f4\u63a5\u5c06\u6a21\u5f0f\u4e32\u5bf9\u51c6fail\u5b57\u7b26\u7684\u4e0b\u4e00\u4e2a\u5b57\u7b26<\/p>\n
DFA\u7248\u672c<\/h3>\n
\u5c06\u5b57\u7b26\u4f4d\u7f6e\u770b\u4f5c\u72b6\u6001\uff0c\u5b57\u7b26\u4e32\u5339\u914d\u53ef\u770b\u4f5c\u6709\u7a77\u72b6\u6001\u673a\u7684\u72b6\u6001\u8f6c\u79fb<\/p>\n
DFA\u6570\u7ec4\u6784\u5efa\u72b6\u6001\u8f6c\u79fb\u8868\uff0c\u6784\u5efa\u8868\u548c\u5339\u914d\u65f6\uff0c\u5339\u914d\u6210\u529f\u8fdb\u5165\u4e0b\u4e00\u4e2a\u72b6\u6001\uff0c\u5339\u914d\u5931\u8d25\u56de\u9000\u5230\u67d0\u4e2a\u72b6\u6001<\/p>\n
    int KMP(string s, string p)\n    {\n        int M = p.length();\n        int N = s.length();\n        int R = 128;\n        int DFA[R][M];\n\n        memset(DFA, 0, sizeof(DFA));\n        DFA[p[0]][0] = 1;\n        for(int state = 1, pre = 0; state < M; state++)\n        {\n            for(int loca = 0; loca < R; loca++)\n                DFA[loca][state] = DFA[loca][pre];\n            DFA[p[state]][state] = state + 1;\n            pre = DFA[p[state]][pre];\n        }\n\n        int i = 0, state = 0;\n        for(; i < N && state < M; i++)\n            state = DFA[s[i]][i];\n        if(state == M) return i - M;\n        return N;\n    }<\/code><\/pre>\n
Boyer-Moore<\/h2>\n
\u6a21\u5f0f\u4e32\u4ece\u5934\u5230\u5c3e\u63a8\u8fdb\uff0c\u5339\u914d\u65f6\u4ece\u53f3\u5411\u5de6\u5339\u914d\uff0c\u5339\u914d\u5931\u8d25\u5219\u63a8\u8fdb\u6a21\u5f0f\u4e32\u8df3\u6b65\uff0c\u53ef\u8fbeO(N\/M)<\/p>\n
Boyer-Moore\u5339\u914d\u6210\u529f\u65f6\u65e0\u9700\u8ba1\u7b97\u8df3\u6b65\u503c\u76f4\u63a5\u8fd4\u56de\u7d22\u5f15<\/p>\n
\u6bcf\u8f6e\u6bd4\u8f83\u7684\u9996\u4e2a\u5339\u914d\u5931\u8d25\u5b57\u7b26fail\u82e5\u5728\u6a21\u5f0f\u4e32\u4e2d\uff0c\u76f4\u63a5\u5c06\u6a21\u5f0f\u4e32\u4e2d\u6700\u53f3\u4fa7fail\u5b57\u7b26\u5bf9\u9f50\u5b57\u7b26\u4e32\u4e2d\u7684fail<\/p>\n
\u82e5\u4e0a\u8ff0\u60c5\u51b5\u5bfc\u81f4\u6a21\u5f0f\u4e32\u5411\u5de6\u5012\u9000\uff0c\u76f4\u63a5\u5c06\u6a21\u5f0f\u4e32\u5411\u53f3\u63a8\u8fdb\u4e00\u4e2a\u5b57\u7b26<\/p>\n
\u82e5fail\u82e5\u4e0d\u5728\u6a21\u5f0f\u4e32\u4e2d\uff0c\u5219\u542b\u6709fail\u7684\u5b50\u4e32\u5747\u65e0\u6cd5\u5339\u914d\uff0c\u76f4\u63a5\u5c06\u6a21\u5f0f\u4e32\u5de6\u4fa7\u5bf9\u9f50fail\u7684\u4e0b\u4e00\u4e2a\u5b57\u7b26<\/p>\n
int BoyerMoore(string s, string p)\n{\n    int M = p.length();\n    int N = s.length();\n    int R = 128;\n    int r[R];\n    int skip;\n\n    memset(r, -1, sizeof(r));\n    for (int i = 0; i < M; i++)\n        r[p[i]] = i;\n\n    for (int i = 0; i <= N - M; i += skip)\n    {\n        skip = 0;\n        for (int j = M - 1; j >= 0; j--)\n            if (s[i + j] != p[j])\n            {\n                skip = j - r[s[i + j]];\n                if (skip < 1) skip = 1;\n                break;\n            }\n        if (skip == 0) return i;\n    }\n    return N;\n}<\/code><\/pre>\n
Rabin-Karp<\/h2>\n
\u8ba1\u7b97\u6a21\u5f0f\u4e32\u548c\u7b49\u957f\u5b50\u4e32\u7684\u54c8\u5e0c\u503c\u5e76\u6bd4\u8f83\uff0c\u54c8\u5e0c\u503c\u4e0d\u540c\u4e00\u5b9a\u4e0d\u5339\u914d\u518d\u63a8\u8fdb\u91cd\u590d\uff0c\u4f7f\u7528BKDR\u9700O(nm)\u65f6\u95f4<\/p>\n
\u54c8\u5e0c\u503c\u76f8\u540c\u7684\u4e24\u5b57\u7b26\u4e32\u4e3a\u76f8\u540c\u4e32\u6216\u54c8\u5e0c\u51b2\u7a81\uff0c\u4e3a\u4fdd\u8bc1\u6b63\u786e\u6027\u6b64\u65f6\u9010\u4f4d\u6bd4\u8f83\u5b57\u7b26\u4e32\uff0c\u5b9e\u9645\u51b2\u7a81\u53ef\u80fd\u6027\u6781\u5c0f\u65e0\u9700\u518d\u6b21\u6bd4\u8f83<\/p>\n
Rabin-Karp\u5728\u524d\u4e00\u4e32\u54c8\u5e0c\u503c\u57fa\u7840\u4e0a\u8ba1\u7b97\u5f53\u524d\u4e32\u54c8\u5e0c\u503c\uff0c\u53ef\u8fbe\u7ebf\u6027\u590d\u6742\u5ea6<\/p>\n
int size;\nint hex;\n\nlong BKDRhash(string s, int len)\n{\n    long hash = 0;\n    for(int i = 0; i < len; i++)\n        hash = (hash * hex + s[i]) % size;\n    return hash;\n}\n\nint RabinKarp(string s, string p)\n{\n    int M = p.length();\n    int N = s.length();\n    long pHash = BKDRhash(p, M);\n    long sHash = BKDRhash(s.substr(0, M), M);\n\n    for(int i = 0; i <= N - M; i++)\n        if(pHash == sHash) return BrutalForce(s.substr(i, M), p);\n        else if(i != N - M) sHash = ((sHash - s[i] * pow(hex, M - 1)) * hex + s[i + 1]) % size;\n\n    return N;\n}<\/code><\/pre>\n
AC\u81ea\u52a8\u673a<\/h2>\n
\u9884\u5904\u7406\u6a21\u5f0f\u4e32\u751f\u6210\u72b6\u6001\u8868\uff0c\u6839\u636e\u8bfb\u5165\u7684\u5b57\u7b26\u8df3\u8f6c\u72b6\u6001\uff0c\u53ef\u8fdb\u884c\u591a\u7ef4\u5b57\u7b26\u4e32\u5339\u914d<\/p>\n","protected":false},"excerpt":{"rendered":"
\u66b4\u529b\u5339\u914d \u6a21\u5f0f\u4e32\u4ece\u5934\u5230\u5c3e\u63a8\u8fdb\uff0c\u5339\u914d\u65f6\u4ece\u5de6\u5411\u53f3\u5339\u914d\uff0c\u5339\u914d\u5931\u8d25\u65f6\u5411\u524d\u63a8\u8fdb\u4e00\u4e2a\u5b57\u7b26 int BrutalForce( … <\/p>\n
\u7ee7\u7eed\u9605\u8bfb\u201c\u4e32\u7684\u6a21\u5f0f\u5339\u914d – \u8d85\u8d8a\u7ebf\u6027\u65f6\u95f4\u5bfb\u627e\u5b50\u4e32\u201d<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[12],"tags":[13],"jetpack_featured_media_url":"","_links":{"self":[{"href":"http:\/\/139.196.114.170\/index.php?rest_route=\/wp\/v2\/posts\/481"}],"collection":[{"href":"http:\/\/139.196.114.170\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/139.196.114.170\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/139.196.114.170\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/139.196.114.170\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=481"}],"version-history":[{"count":40,"href":"http:\/\/139.196.114.170\/index.php?rest_route=\/wp\/v2\/posts\/481\/revisions"}],"predecessor-version":[{"id":2743,"href":"http:\/\/139.196.114.170\/index.php?rest_route=\/wp\/v2\/posts\/481\/revisions\/2743"}],"wp:attachment":[{"href":"http:\/\/139.196.114.170\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=481"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/139.196.114.170\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=481"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/139.196.114.170\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=481"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}