{"id":2036,"date":"2021-09-13T18:57:29","date_gmt":"2021-09-13T10:57:29","guid":{"rendered":"http:\/\/47.101.202.111\/?p=2036"},"modified":"2023-04-07T11:45:39","modified_gmt":"2023-04-07T03:45:39","slug":"algorithm-greedy-strategy","status":"publish","type":"post","link":"http:\/\/139.196.114.170\/?p=2036","title":{"rendered":"\u201c\u77ed\u89c6\u201d\u4e5f\u80fd\u8fbe\u5230\u6700\u4f18 – \u8d2a\u5fc3\u7b97\u6cd5\u7cbe\u8bb2"},"content":{"rendered":"

\u8d2a\u5fc3\u601d\u60f3<\/h2>\n

\u4e00\u822c\u7528\u6765\u89e3\u51b3\u201c\u6700\u4f18\u5316\u201d\u95ee\u9898\u3002\u603b\u662f\u4ece\u5c40\u90e8\u9009\u53d6\u6700\u201c\u597d\u201d\u7684\u7ed3\u679c\uff0c\u901a\u8fc7\u5c40\u90e8\u6700\u4f18\u6765\u63a8\u5bfc\u5168\u5c40\u6700\u4f18\u3002<\/p>\n

\u8d2a\u5fc3\u7b56\u7565\u5e76\u4e0d\u603b\u662f\u6709\u89e3\uff0c\u4e5f\u5e76\u4e0d\u603b\u662f\u6709\u6700\u4f18\u89e3\u3002\u56e0\u6b64\u5168\u5c40\u6700\u4f18\u89e3\u4e00\u822c\u9009\u7528 \u52a8\u6001\u89c4\u5212<\/strong> \u548c\u5176\u5b83 \u641c\u7d22\u7b56\u7565<\/strong><\/p>\n

\u8d2a\u5fc3\u53ef\u83b7\u5f97\u6700\u4f18\u89e3\u7684\u6761\u4ef6\u662f\u95ee\u9898\u5177\u6709 \u6700\u4f18\u5b50\u7ed3\u6784\u6027\u8d28<\/strong>\uff0c\u5373\u6bcf\u4e00\u6b65\u9009\u62e9\u7684\u6700\u4f18\u89e3\u90fd\u662f\u5168\u5c40\u6700\u4f18\u89e3\u4e2d\u7684\u4e00\u4e2a\u89e3\u3002<\/p>\n

\u6838\u5fc3\u601d\u8def<\/h3>\n

\u627e\u5230\u4e00\u4e2a \u6307\u6807<\/strong>\uff0c\u5bf9\u8fd9\u4e00\u6307\u6807\u7684\u8d2a\u5fc3\u7b56\u7565\u6ee1\u8db3\u6700\u4f18\u5b50\u7ed3\u6784\u6027\u8d28\u3002\u6307\u6807\u53ef\u4ee5\u662f\u9898\u7ed9\u7684\u9650\u5236\u6761\u4ef6\uff0c\u4e5f\u53ef\u4ee5\u662f\u53e6\u5916\u6784\u9020\u7684\u5c3a\u5ea6\u3002\u4e00\u822c\u4f1a\u4f7f\u7528 \u6392\u5e8f<\/strong> \u9884\u5904\u7406\u6570\u636e\u6765\u8f85\u52a9<\/p>\n

\u7ecf\u5178\u95ee\u9898\u601d\u8def<\/h3>\n

\u51d1\u94b1\u6570\uff1a\u94b1\u5e01\u9762\u503c\u7531\u5927\u5230\u5c0f\u9009\u53d6
\n\u4efb\u52a1\u5b89\u6392\uff1a\u7ed3\u675f\u65f6\u95f4\u4ece\u5c0f\u5230\u5927\u9009\u53d6
\n\u591a\u673a\u8c03\u5ea6\uff1a\u6267\u884c\u65f6\u95f4\u4ece\u5927\u5230\u5c0f\u9009\u53d6
\n\u533a\u95f4\u8986\u76d6\uff1a\u9009\u5b9a\u533a\u95f4\u4e00\u7aef\uff0c\u9009\u5b9a\u533a\u95f4\u5185\u4ece\u957f\u5230\u77ed\u9009\u53d6
\n\u54c8\u592b\u66fc\u7f16\u7801\uff1a\u8282\u70b9\u4ece\u5c0f\u5230\u5927\u9009\u53d6
\nDijkstra\uff1a\u5b50\u8def\u5f84\u957f\u5ea6\u4ece\u5c0f\u5230\u5927\u9009\u53d6<\/p>\n

\u5b9e\u6218\u5e94\u7528<\/h3>\n

\u4e70\u82f9\u679c<\/h4>\n

\u53ea\u6709\u5c0f\u888b6\u4e2a\u548c\u5927\u888b8\u4e2a\u4e24\u79cd\u89c4\u683c\uff0c\u95ee\u4e70N\u4e2a\u82f9\u679c\u6700\u5c11\u51e0\u888b\u3002\u7b56\u7565\u662f\u5c3d\u53ef\u80fd\u62ff\u5927\u888b\u5b50\uff0c\u53ef\u5c06\u5927\u888b\u4ece $\\scriptsize n \/ 8$ \u5f00\u59cb\u5012\u5e8f\u679a\u4e3e\u3002\u672c\u9898\u91c7\u7528\u6a21\u8fd0\u7b97\u76f4\u63a5\u5047\u8bbe\u5168\u62ff\u5927\u888b\uff0c$\\scriptsize 6$ \u548c $\\scriptsize 8$ \u7684\u6570\u5b57\u7ec4\u5408\u5bf9 $\\scriptsize 8$ \u53d6\u6a21\u7ed3\u679c\u4e3a $\\scriptsize 0\u30012\u30014\u30016$
\n\u5269\u4f59 $\\scriptsize 2$ \u4e2a\u65f6\u53ef\u7528 $\\scriptsize 6+6+6$ \u66ff\u6362 $\\scriptsize 8\\times 2+2$\uff0c\u6b64\u60c5\u51b5\u8981\u6c42 $\\scriptsize N \\geqslant 18$\u3002
\n\u5269\u4f59 $\\scriptsize 4$ \u4e2a\u65f6\u53ef\u7528 $\\scriptsize 6+6$ \u66ff\u6362 $\\scriptsize 8+4$\uff0c\u6b64\u60c5\u51b5\u8981\u6c42 $\\scriptsize N \\geqslant 12$\u3002
\n\u5269\u4f59 $\\scriptsize 6$ \u4e2a\u65f6\u53ef\u7528\u76f4\u63a5\u7528\u5c0f\u888b\u3002<\/p>\n

#include <iostream>\nusing namespace std;\nint main() {\n    int N;\n    scanf(\"%d\", &N);\n    if(N <= 5 || N == 10) {\n        printf(\"Cannot!\");\n        return 0;\n    }\n    switch(N % 8) {\n        case 0: printf(\"%d\", N \/ 8); break;\n        case 2:\n        case 4:\n        case 6: printf(\"%d\", N \/ 8 + 1); break;\n        default: printf(\"Cannot!\"); break;\n    }\n    return 0;\n}\n<\/code><\/pre>\n
PAT-B1023 \u6700\u5c0f\u6570<\/h4>\n
\u5148\u9009\u975e\u96f6\u6700\u5c0f\u9996\u4f4d\uff0c\u518d\u6309\u6570\u5b57\u7531\u5c0f\u5230\u5927\u8f93\u51fa<\/p>\n
#include <iostream>\nusing namespace std;\nint main() {\n    int s = 10, cnt[10];\n    for (int i = 0; i < 10; i++) {\n        scanf(\"%d\", &cnt[i]);\n        if (i < s && i && cnt[i]) {\n            s = i;\n            cnt[i]--;\n        }\n    }\n    printf(\"%d\", s);\n    for (int i = 0; i < 10; i++)\n        while (cnt[i]--)\n            printf(\"%d\", i);\n    return 0;\n}\n<\/code><\/pre>\n
PAT-A1070 \u6700\u5927\u5229\u6da6<\/h4>\n
\u9898\u610f\u8f6c\u4e3a\u6709\u9650\u5e93\u5b58\u7ec4\u5408\u53ef\u83b7\u5f97\u7684\u6700\u5927\u4ef7\u683c
\n\u8d2a\u5fc3\u601d\u60f3\u9009\u5b9a\u5355\u4ef7\u4e3a\u6307\u6807\uff0c\u4ece\u5927\u5230\u5c0f\u586b\u5145\u5e93\u5b58\u5373\u53ef\uff0c\u76f4\u5230\u586b\u6ee1\u7ed3\u675f<\/p>\n
\n
\u2299_\u2299<\/strong> Q\uff1a\u5e93\u5b58\u8fd8\u53ef\u4ee5\u7ec4\u5408\u7684\uff1f\u6574\u61f5\u4e86\uff1f<\/p>\n
(\u222b\u30fb\u03c9\u30fb)\u222b<\/strong> A\uff1a\u4ece\u9ad8\u5355\u4ef7\u5230\u4f4e\u5355\u4ef7\u4f9d\u6b21\u6263\u9664\u8d27\u54c1\u5c31\u597d\u4e86\u3002\u5982\u679c\u8d27\u54c1\u5e93\u5b58\u6bd4\u5269\u4f59\u76ee\u6807\u5e93\u5b58\u8fd8\u591a\uff0c\u5f53\u524d\u8d27\u54c1\u5c31\u662f\u6700\u540e\u4e00\u4e2a\uff0c\u4e14\u4e3a\u90e8\u5206\u7ec4\u5408\u3002\u5982\u679c\u5269\u4f59\u76ee\u6807\u5e93\u5b58\u591a\uff0c\u8bf4\u660e\u5f53\u524d\u8d27\u54c1\u5168\u8981\u4e86\u3002<\/p>\n
\u2220(\u00b0\u309d\u00b0\uff09<\/strong> Q\uff1a\u7ed3\u6784\u4f53\u6570\u7ec4\u6392\u5e8f\u4e00\u76f4\u62a5\u7c7b\u578b\u8f6c\u6362\u51fa\u9519\u4ec0\u4e48\u9b3c\uff1f<\/p>\n
(\u0e51\u2022\u0300\u0434\u2022\u0301\u0e51)<\/strong> A\uff1a\u81ea\u5b9a\u4e49\u6392\u5e8f\u51fd\u6570\uff0c\u5165\u53c2\u662f\u4e24\u4e2a \u7ed3\u6784\u4f53\u7c7b\u578b<\/strong>\uff01\u4e00\u5b9a\u8981\u8bb0\u4f4f\uff01<\/p>\n
\n
#include <iostream>\n#include <algorithm>\nusing namespace std;\n\nconst int maxn = 1001;\nstruct obj {\n    double ivt;\n    double unit;\n    double total;\n} o[maxn];\n\nbool cmp(obj a, obj b) {\n    return a.unit > b.unit;\n}\n\nint main() {\n    int N;\n    double maxP = 0, D;\n    scanf(\"%d %lf\", &N, &D);\n    for (int i = 0; i < N; i++)\n        scanf(\"%lf\", &o[i].ivt);\n    for (int i = 0; i < N; i++) {\n        scanf(\"%lf\", &o[i].total);\n        o[i].unit = o[i].total \/ o[i].ivt;\n    }\n    sort(o, o + N, cmp);\n\n    for (int i = 0; i < N && D; i++) {\n        int ivt = o[i].ivt;\n        if (ivt <= D) {\n            maxP += o[i].total;\n            D -= ivt;\n        }\n        else {\n            maxP += o[i].unit * D;\n            D = 0;\n        }\n    }\n    printf(\"%.2f\", maxP);\n    return 0;\n}\n<\/code><\/pre>\n
PAT-A1033 \u6700\u5c0f\u6cb9\u4ef7<\/h4>\n
\u603b\u4ef7\u6700\u4f4e\uff0c\u5373\u76ee\u6807\u662f\u8ba9\u9ad8\u5355\u4ef7\u533a\u95f4\u5c3d\u53ef\u80fd\u77ed\uff0c\u77ed\u5355\u4ef7\u533a\u95f4\u5c3d\u53ef\u80fd\u957f\u3002\u6bcf\u6b21\u9009\u62e9\u6700\u8fd1\u7684\u4ef7\u683c\u66f4\u4f4e\u7684\u6cb9\u7ad9\uff0c\u5982\u679c\u53ef\u8fbe\u8303\u56f4\u5185\u6ca1\u6709\u4ef7\u683c\u66f4\u4f4e\u7684\u5219\u9009\u62e9\u53ef\u8fbe\u7ad9\u70b9\u4e2d\u6700\u4f4e\u7684\u4e00\u4e2a<\/p>\n
\n
Q\uff1a\u6211\u7684\u7b56\u7565\u662f\u4ef7\u683c\u4ece\u4f4e\u5230\u9ad8\u9009\u53d6\uff0c\u6bcf\u6b21\u9009\u53d6\u6700\u4fbf\u5b9c\u4e14\u53ef\u8fbe\u7684\u6cb9\u7ad9\uff0c\u8fd9\u6837\u4e3a\u4ec0\u4e48\u4e0d\u662f\u6700\u4f18\uff1f<\/p>\n
A\uff1a\u4f60\u8fd9\u4e2a\u7b56\u7565\u7684\u6548\u679c\u662f\u53ef\u8fbe\u7ec8\u70b9\u7684\u6240\u6709\u65b9\u6848\u4e2d \u5355\u4ef7\u548c\u6700\u4f4e<\/strong>\u3002\u6253\u4e2a\u6bd4\u65b9\uff1a\u4f60\u662f\u53bb\u5341\u4e2a\u73ed\u6311\u4e86\u6210\u7ee9\u6700\u597d\u7684\u5b66\u751f\uff0c\u6311\u51fa\u7684\u5374\u4e0d\u4e00\u5b9a\u662f\u5e74\u7ea7\u524d\u5341\u3002\u800c\u6211\u4eec\u7684\u76ee\u6807\u662f \u603b\u4ef7\u6700\u4f4e\uff0c\u4e0d\u6b62\u6709\u5355\u4ef7\uff0c\u8fd8\u6709\u8ddd\u79bb\u7684\u56e0\u7d20<\/strong>\u3002\u5982\u4e0b\u4f8b $$\\scriptsize U_{\u5f53\u524d\u7ad9} \\rightarrow V_{\u4ef7\u683c\u4ecb\u4e8eU,V\u7ad9} \\rightarrow W_{\u4e0b\u4e00\u4ef7\u683c\u6700\u4f4e\u7ad9}$$ \u8981\u6c42\u5f53\u524d\u7ad9\u5230\u4e0b\u4e00\u6700\u4f4e\u4ef7\u683c\u7ad9\u4e4b\u95f4\u7684\u4ef7\u683c\u4e5f\u8981\u6700\u4f4e\uff0c\u660e\u663e\u662f\u9700\u8981\u8d70V\u7684\uff0c\u800c\u4f60\u7684\u7b56\u7565\u5ffd\u7565\u6389\u4e86\u3002<\/p>\n
\n

<\/code><\/pre>\n
PAT A1037 \u6700\u5927\u4e58\u79ef\u548c<\/h4>\n
\u601d\u8def\u662f\u53d6\u540c\u53f7\u7684\u4e24\u6700\u5927\u7edd\u5bf9\u503c\u6570\u4e58\u79ef\uff0c\u5373\u5206\u522b\u53d6\u6392\u5e8f\u540e\u4e24\u4e2a\u5e8f\u5217\u7684\u4e24\u7aef\uff0c\u4e24\u7aef\u518d\u4f9d\u6b21\u5411\u5185\u6536\u7f29\u63a8\u8fdb\u5373\u53ef\u3002<\/p>\n
\n
\u2220(+_+)?<\/strong> Q\uff1a\u6211\u786e\u5b9e\u662f\u6309\u7167\u672c\u9898\u601d\u60f3\u5b9e\u73b0\u7684\uff0c\u53ea\u4e0d\u8fc7\u6539\u7528\u4e86\u4e00\u4e2a\u5927\u5faa\u73af\u7684\u53cc\u6307\u9488\u65b9\u6cd5\uff0c\u5148\u9012\u589e\u5de6\u4fa7\uff0c\u518d\u9012\u51cf\u53f3\u4fa7\uff0c\u7528\u4e58\u79ef\u5927\u4e8e0\u6765\u5224\u65ad\u52a0\u548c\uff0c\u68c0\u6d4b\u70b92\u600e\u4e48\u5c31\u6b7b\u6d3b\u901a\u4e0d\u8fc7\u5462\uff1f<\/p>\n
\uff08\u9003 \u03b5=\u03b5=\u03b5=\u250f()\u251b<\/strong> A\uff1a\u4e0d\u8981\u6b7b\u78d5\u8fc7\u4e0d\u53bb\u7684\u6837\u4f8b\uff0c\u53ef\u4ee5\u9010\u4e2a\u5c06\u8f93\u5165\u6570\u636e\u901a\u8fc7\u4e8c\u5206\u6cd5\u731c\u51fa\u8303\u56f4\uff0c\u731c\u5bf9\u7684\u8303\u56f4\u8f93\u51fa\u4e00\u4e2a\u9519\u8bef\u7b54\u6848\uff0c\u5426\u5219\u7ed9\u4ed6\u65e0\u9650\u5faa\u73af\u8ba9\u63d0\u4ea4\u51fa\u73b0\u8d85\u65f6\uff0c\u8fd9\u6837\u4e00\u5b9a\u6b21\u6570\u540e\u5c31\u53ef\u786e\u5b9a\u51fa\uff08\u8bfb\u4e66\u4eba\u7684\u4e8b\u600e\u4e48\u80fd\u53eb\u5077\u5462\uff09\u51c6\u786e\u6837\u4f8b\uff08\u59e5\u59e5\u522b\u6253\u6211\uff01\u6e9c\u8d70\u2026\uff09\u3002\u56de\u5230\u9898\u4e0a\u6765\uff0c\u5982\u679c \u4e24\u4e2a\u90fd\u662f\u6b63\u5e8f\u5217\u7684\u8bdd\uff0c\u5e94\u8be5\u4ece\u53f3\u5411\u5de6<\/strong>\uff0c\u4e0d\u80fd\u591f\u4ece\u5de6\u5411\u53f3\u5427\uff01\u53ea\u6709\u4e58\u79ef>0\u662f\u4e0d\u591f\u7684\uff0c\u9700\u8981\u5224\u65ad \u4e24\u6570\u540c\u8d1f\u518d\u9012\u589e\u5de6\uff0c\u4e24\u6570\u540c\u6b63\u518d\u9012\u51cf\u53f3<\/strong>\u3002\u540c\u65f6\u4e0d\u8981\u5fd8\u8bb0 \u6307\u9488\u4e0d\u80fd\u8d8a\u754c<\/strong>\u3002\u6700\u540e \u4e0d\u80fd\u628a\u4e58\u79ef=0\u5212\u8fdb\u6765<\/strong>\uff0c\u5982\u4e0b\u6837\u4f8b\uff0c\u4f1a\u5bfc\u81f4\u7d22\u5f15\u4e3a3\u65f6\u524d\u540e\u4e24\u4e2a\u65b9\u5411\u91cd\u590d\u9519\u8bef\u8ba1\u7b97\uff1b\u5b9e\u9645\u4e0a\u78b0\u52300\u4e5f\u6ca1\u6709\u5fc5\u8981\u52a0\u8fdb\u6765\uff0c\u4e0d\u5f71\u54cd\u7ed3\u679c\u3002<\/p>\n
5 -1 0 2 3\n3 -3 0 1\n<\/code><\/pre>\n
\n
#include <iostream>\n#include <algorithm>\nusing namespace std;\n\nconst int maxn = 100001;\nint c[maxn], p[maxn];\n\nint main() {\n    int nc, np;\n\n    scanf(\"%d\", &nc);\n    for (int i = 0; i < nc; i++)\n        scanf(\"%lld\", &c[i]);\n\n    scanf(\"%d\", &np);\n    for (int i = 0; i < np; i++)\n        scanf(\"%lld\", &p[i]);\n\n    sort(c, c + nc);\n    sort(p, p + np);\n\n    int lc = 0, hc = nc - 1;\n    int lp = 0, hp = np - 1;\n    long long maxR = 0;\n\n    while (lc < hc && lp < hp && c[lc] < 0 && p[lp] < 0) {\n        maxR += c[lc] * p[lp];\n        lc++;\n        lp++;\n    }\n\n    while (hc >= 0 && hp >= 0 && c[hc] > 0 && p[hp] > 0) {\n        maxR += c[hc] * p[hp];\n        hc--;\n        hp--;\n    }\n\n    printf(\"%lld\", maxR);\n\n    return 0;\n}\n<\/code><\/pre>\n
PAT-A1067 \u6700\u5c0f\u4ea4\u6362\u6b21\u6570<\/h4>\n
\n
Q\uff1a<\/p>\n
A\uff1a0\u6bcf\u4ea4\u6362\u56de\u539f\u4f4d\u5c31\u591a\u4e00\u6b21<\/p>\n
\n","protected":false},"excerpt":{"rendered":"
\u8d2a\u5fc3\u601d\u60f3 \u4e00\u822c\u7528\u6765\u89e3\u51b3\u201c\u6700\u4f18\u5316\u201d\u95ee\u9898\u3002\u603b\u662f\u4ece\u5c40\u90e8\u9009\u53d6\u6700\u201c\u597d\u201d\u7684\u7ed3\u679c\uff0c\u901a\u8fc7\u5c40\u90e8\u6700\u4f18\u6765\u63a8\u5bfc\u5168\u5c40\u6700\u4f18\u3002 \u8d2a\u5fc3\u7b56\u7565\u5e76\u4e0d … <\/p>\n
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