{"id":432027,"date":"2021-04-18T12:33:32","date_gmt":"2021-04-18T04:33:32","guid":{"rendered":"http:\/\/4563.org\/?p=432027"},"modified":"2021-04-18T12:33:32","modified_gmt":"2021-04-18T04:33:32","slug":"%e9%ab%98%e9%a2%91%e9%a2%98%e9%9d%a2%e8%af%95%e7%bb%8f%e5%85%b8%e9%a2%98%e7%9b%ae-%e8%82%a1%e7%a5%a8%e4%b9%b0%e5%8d%96%e9%97%ae%e9%a2%98","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=432027","title":{"rendered":"[\u9ad8\u9891\u9898]\u9762\u8bd5\u7ecf\u5178\u9898\u76ee–\u80a1\u7968\u4e70\u5356\u95ee\u9898"},"content":{"rendered":"
\n
\n
\n

[\u9ad8\u9891\u9898]\u9762\u8bd5\u7ecf\u5178\u9898\u76ee–\u80a1\u7968\u4e70\u5356\u95ee\u9898 <\/h1>\n

<\/p>\n

\n
\u8cc7\u6df1\u5927\u4f6c : youthes <\/span> <\/i> 9<\/span> <\/div>\n
<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n
\u4e0d\u5f97\u4e0d\u8bf4\uff0c\u5237\u9898\u5df2\u7ecf\u548c\u722c\u5c71\u3001\u6e9c\u5a03\u4e00\u6837\uff0c\u6210\u4e3a\u6e7e\u533a\u4e09\u4fd7\uff0c\u57fa\u672c\u51e0\u4e2a\u6e7e\u533a\u7684\u5de5\u7a0b\u5e08\u78b0\u5728\u4e00\u8d77\uff0c\u8ba8\u8bba\u7684\u8bdd\u9898\u603b\u8df3\u4e0d\u51fa\u8fd9\u4e2a\u5708\u3002\u722c\u5c71\uff0c\u54e6\u4e0d\uff0c\u5237\u9898\u4f5c\u4e3a\u4e00\u4e2a\u8d2f\u7a7f\u7801\u519c\u6574\u4e2a\u804c\u4e1a\u751f\u6daf\u7684\u5fc5\u987b\u54c1\uff08\u5c31\u7b97\u662f\u6211\u76ee\u524d\u5446\u7684\u5fae\u8f6f\u8c37\u6b4c\u8fd9\u79cd\u517b\u8001\u516c\u53f8\u4e5f\u603b\u5f97\u8df3\u4e00\u8df3\uff0c\u6bd5\u7adf\u96ea\u82b1\u7684\u5927\u5305\u88f9\u662f\u771f\u9999\u554a\uff09\uff0c\u51e0\u5e74\u6765\u57fa\u672c\u6bcf\u5929\u4e0d\u95f4\u65ad\u7684\u5237\uff0c\u7b97\u662f\u5bf9\u8fd9\u4e00\u5757\u7565\u6709\u5fc3\u5f97\u3002\u5e16\u5b50\u7684\u524d\u534a\u90e8\u5206\u60f3\u5206\u4eab\u4e00\u4e9b\u6211\u4f5c\u4e3a\u9762\u8bd5\u5b98\u7684\u5e38\u51fa\u7684\u4e00\u4e9b\u7ecf\u5178\u9898\u76ee\uff0c\u4ee5\u53ca\u9898\u76ee\u601d\u8def\u7684\u89e3\u6790\u4ee5\u53ca\u4e00\u4e9b\u540c\u7c7b\u9898\u7684\u5f52\u7eb3\uff0c\u5e16\u5b50\u7684\u540e\u534a\u90e8\u5206\u6211\u4f1a\u53c2\u8003\u575b\u53cb\u4eec\u7684\u7559\u8a00\u548c\u62cd\u7816\uff0c\u6765\u51b3\u5b9a\u540e\u9762\u7684\u8d70\u5411<\/p>\n

\u5e16\u5b50\u4f1a\u957f\u671f\u4fdd\u6301\u66f4\u65b0\uff0c\u53ea\u8981\u662f\u5e26\u5a03\u7684\u95f4\u9699\u5c31\u4f1a\u5077\u5077\u4e0a\u6765\u66f4\u4e00\u4e0b\uff0c\u5c3d\u91cf\u4fdd\u6301\u6bcf\u5468\u4e24\u66f4\u3002<\/p>\n

\u672c\u671f\u6211\u4eec\u5206\u4eab \u9762\u8bd5\u7ecf\u5178\u9898\u76ee–\u80a1\u7968\u4e70\u5356\u95ee\u9898<\/p>\n

\u7531\u4e8e\u592a\u591a\u4eba\u52a0\u6211 VX\uff0c\u6211\u4e5f\u521b\u5efa\u4e86\u4e00\u4e2a\u7b97\u6cd5\u5de5\u4f5c\u4ea4\u6d41\u7fa4\uff0c\u5927\u5bb6\u611f\u5174\u8da3\u53ef\u4ee5\u52a0\u6211\u62c9\u4f60\u8fdb\u7fa4<\/p>\n

\u6211\u7684 VX\uff1asxxzs3998 \u4e0d\u7ba1\u662f\u5177\u4f53\u7684\u9898\u76ee\u8ba8\u8bba\u8fd8\u662f\u7ed9\u5e16\u5b50\u7684\u5efa\u8bae\u548c\u62cd\u7816\uff0c\u6216\u8005\u60f3\u8fdb\u7fa4\u90fd\u6b22\u8fce\u6dfb\u52a0\uff08\u8bb0\u5f97\u52a0\u6211\u8981\u5907\u6ce8 v2 \uff09 <\/p><\/div>\n

\u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (8<\/span>) <\/div>\n
<\/div>\n<\/p><\/div>\n<\/p><\/div>\n
    \n
  • \n
    \n
    \n
    \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : youthes <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u9898\u76ee\u6700\u6cdb\u5316\u7684\u5f62\u5f0f<\/p>\n

    \u7ed9\u5b9a\u4e00\u4e2a\u6574\u6570\u6570\u7ec4\u00a0prices\uff0c\u5b83\u7684\u7b2c i \u4e2a\u5143\u7d20\u00a0prices[i] \u662f\u4e00\u652f\u7ed9\u5b9a\u7684\u80a1\u7968\u5728\u7b2c i \u5929\u7684\u4ef7\u683c\u3002<\/p>\n

    \u8bbe\u8ba1\u4e00\u4e2a\u7b97\u6cd5\u6765\u8ba1\u7b97\u4f60\u6240\u80fd\u83b7\u53d6\u7684\u6700\u5927\u5229\u6da6\u3002\u4f60\u6700\u591a\u53ef\u4ee5\u5b8c\u6210 k \u7b14\u4ea4\u6613\u3002<\/p>\n

    \u6ce8\u610f\uff1a\u4f60\u4e0d\u80fd\u540c\u65f6\u53c2\u4e0e\u591a\u7b14\u4ea4\u6613\uff08\u4f60\u5fc5\u987b\u5728\u518d\u6b21\u8d2d\u4e70\u524d\u51fa\u552e\u6389\u4e4b\u524d\u7684\u80a1\u7968\uff09\u3002<\/p>\n

    \u00a0<\/p>\n

    \u793a\u4f8b 1\uff1a<\/p>\n

    \u8f93\u5165\uff1ak = 2, prices = [2,4,1]
    \u8f93\u51fa\uff1a2
    \u89e3\u91ca\uff1a\u5728\u7b2c 1 \u5929 (\u80a1\u7968\u4ef7\u683c = 2) \u7684\u65f6\u5019\u4e70\u5165\uff0c\u5728\u7b2c 2 \u5929 (\u80a1\u7968\u4ef7\u683c = 4) \u7684\u65f6\u5019\u5356\u51fa\uff0c\u8fd9\u7b14\u4ea4\u6613\u6240\u80fd\u83b7\u5f97\u5229\u6da6 = 4-2 = 2 \u3002
    \u793a\u4f8b 2\uff1a<\/p>\n

    \u8f93\u5165\uff1ak = 2, prices = [3,2,6,5,0,3]
    \u8f93\u51fa\uff1a7
    \u89e3\u91ca\uff1a\u5728\u7b2c 2 \u5929 (\u80a1\u7968\u4ef7\u683c = 2) \u7684\u65f6\u5019\u4e70\u5165\uff0c\u5728\u7b2c 3 \u5929 (\u80a1\u7968\u4ef7\u683c = 6) \u7684\u65f6\u5019\u5356\u51fa, \u8fd9\u7b14\u4ea4\u6613\u6240\u80fd\u83b7\u5f97\u5229\u6da6 = 6-2 = 4 \u3002
    \u968f\u540e\uff0c\u5728\u7b2c 5 \u5929 (\u80a1\u7968\u4ef7\u683c = 0) \u7684\u65f6\u5019\u4e70\u5165\uff0c\u5728\u7b2c 6 \u5929 (\u80a1\u7968\u4ef7\u683c = 3) \u7684\u65f6\u5019\u5356\u51fa, \u8fd9\u7b14\u4ea4\u6613\u6240\u80fd\u83b7\u5f97\u5229\u6da6 = 3-0 = 3 \u3002<\/p>\n

    \u7b2c\u4e00\u9898\u662f\u53ea\u8fdb\u884c\u4e00\u6b21\u4ea4\u6613\uff0c\u76f8\u5f53\u4e8e k = 1 \uff1b\u7b2c\u4e8c\u9898\u662f\u4e0d\u9650\u4ea4\u6613\u6b21\u6570\uff0c\u76f8\u5f53\u4e8e k = +infinity \uff08\u6b63\u65e0\u7a77\uff09\uff1b\u7b2c\u4e09\u9898\u662f\u53ea\u8fdb\u884c 2 \u6b21\u4ea4\u6613\uff0c\u76f8\u5f53\u4e8e k = 2 \uff1b\u5269\u4e0b\u4e24\u9053\u4e5f\u662f\u4e0d\u9650\u6b21\u6570\uff0c\u4f46\u662f\u52a0\u4e86\u4ea4\u6613\u300c\u51b7\u51bb\u671f\u300d\u548c\u300c\u624b\u7eed\u8d39\u300d\u7684\u989d\u5916\u6761\u4ef6\uff0c\u5176\u5b9e\u5c31\u662f\u7b2c\u4e8c\u9898\u7684\u53d8\u79cd\uff0c\u90fd\u5f88\u5bb9\u6613\u5904\u7406\u3002 <\/div>\n<\/p><\/div>\n<\/li>\n

  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : musi <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    @livid <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : wa007 <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u5047\u5982\u4e00\u5171\u6709 n \u5929\uff0c\u6211\u53ea\u80fd\u60f3\u5230\u4e00\u4e2a n*n*k \u7684\u590d\u6742\u5ea6\u7684\u7b97\u6cd5\u3002<\/p>\n

    \u8fd9\u9898\u76ee\u5c31\u662f\u8ba9\u5c3d\u91cf\u60f3\u51fa\u6700\u4f18\u7684\u89e3\u6cd5\u5427\u3002\u90a3\u4e3b\u80fd\u60f3\u5230\u7684\u6700\u4f18\u7684\u65f6\u95f4\u590d\u6742\u5ea6\u662f\u591a\u5c11\u5462 <\/p><\/div>\n<\/p><\/div>\n<\/li>\n

  • \n
    \n
    \n
    \u8cc7\u6df1\u5927\u4f6c : sherlockwhite <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u8fd9\u9053\u9898\u8001\u7b80\u5355\u4e86 <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
    \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : youthes <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u6211\u4eec\u5177\u4f53\u5230\u6bcf\u4e00\u5929\uff0c\u770b\u770b\u603b\u5171\u6709\u51e0\u79cd\u53ef\u80fd\u7684\u300c\u72b6\u6001\u300d\uff0c\u518d\u627e\u51fa\u6bcf\u4e2a\u300c\u72b6\u6001\u300d\u5bf9\u5e94\u7684\u300c\u9009\u62e9\u300d\u3002\u6211\u4eec\u8981\u7a77\u4e3e\u6240\u6709\u300c\u72b6\u6001\u300d\uff0c\u7a77\u4e3e\u7684\u76ee\u7684\u662f\u6839\u636e\u5bf9\u5e94\u7684\u300c\u9009\u62e9\u300d\u66f4\u65b0\u72b6\u6001\u3002\u542c\u8d77\u6765\u62bd\u8c61\uff0c\u4f60\u53ea\u8981\u8bb0\u4f4f\u300c\u72b6\u6001\u300d\u548c\u300c\u9009\u62e9\u300d\u4e24\u4e2a\u8bcd\u5c31\u884c\uff0c\u4e0b\u9762\u5b9e\u64cd\u4e00\u4e0b\u5c31\u5f88\u5bb9\u6613\u660e\u767d\u4e86\u3002
    for \u72b6\u6001 1 in \u72b6\u6001 1 \u7684\u6240\u6709\u53d6\u503c\uff1a
    for \u72b6\u6001 2 in \u72b6\u6001 2 \u7684\u6240\u6709\u53d6\u503c\uff1a
    for …
    dp[\u72b6\u6001 1][\u72b6\u6001 2][…] = \u62e9\u4f18(\u9009\u62e9 1\uff0c\u9009\u62e9 2…)<\/p>\n

    \u6bd4\u5982\u8bf4\u8fd9\u4e2a\u95ee\u9898\uff0c\u6bcf\u5929\u90fd\u6709\u4e09\u79cd\u300c\u9009\u62e9\u300d\uff1a\u4e70\u5165\u3001\u5356\u51fa\u3001\u65e0\u64cd\u4f5c\uff0c\u6211\u4eec\u7528 buy, sell, rest \u8868\u793a\u8fd9\u4e09\u79cd\u9009\u62e9\u3002\u4f46\u95ee\u9898\u662f\uff0c\u5e76\u4e0d\u662f\u6bcf\u5929\u90fd\u53ef\u4ee5\u4efb\u610f\u9009\u62e9\u8fd9\u4e09\u79cd\u9009\u62e9\u7684\uff0c\u56e0\u4e3a sell \u5fc5\u987b\u5728 buy \u4e4b\u540e\uff0cbuy \u5fc5\u987b\u5728 sell \u4e4b\u540e\u3002\u90a3\u4e48 rest \u64cd\u4f5c\u8fd8\u5e94\u8be5\u5206\u4e24\u79cd\u72b6\u6001\uff0c\u4e00\u79cd\u662f buy \u4e4b\u540e\u7684 rest \uff08\u6301\u6709\u4e86\u80a1\u7968\uff09\uff0c\u4e00\u79cd\u662f sell \u4e4b\u540e\u7684 rest \uff08\u6ca1\u6709\u6301\u6709\u80a1\u7968\uff09\u3002\u800c\u4e14\u522b\u5fd8\u4e86\uff0c\u6211\u4eec\u8fd8\u6709\u4ea4\u6613\u6b21\u6570 k \u7684\u9650\u5236\uff0c\u5c31\u662f\u8bf4\u4f60 buy \u8fd8\u53ea\u80fd\u5728 k > 0 \u7684\u524d\u63d0\u4e0b\u64cd\u4f5c\u3002
    \u5f88\u590d\u6742\u5bf9\u5427\uff0c\u4e0d\u8981\u6015\uff0c\u6211\u4eec\u73b0\u5728\u7684\u76ee\u7684\u53ea\u662f\u7a77\u4e3e\uff0c\u4f60\u6709\u518d\u591a\u7684\u72b6\u6001\uff0c\u8001\u592b\u8981\u505a\u7684\u5c31\u662f\u4e00\u628a\u68ad\u5168\u90e8\u5217\u4e3e\u51fa\u6765\u3002\u8fd9\u4e2a\u95ee\u9898\u7684\u300c\u72b6\u6001\u300d\u6709\u4e09\u4e2a\uff0c\u7b2c\u4e00\u4e2a\u662f\u5929\u6570\uff0c\u7b2c\u4e8c\u4e2a\u662f\u5141\u8bb8\u4ea4\u6613\u7684\u6700\u5927\u6b21\u6570\uff0c\u7b2c\u4e09\u4e2a\u662f\u5f53\u524d\u7684\u6301\u6709\u72b6\u6001\uff08\u5373\u4e4b\u524d\u8bf4\u7684 rest \u7684\u72b6\u6001\uff0c\u6211\u4eec\u4e0d\u59a8\u7528 1 \u8868\u793a\u6301\u6709\uff0c0 \u8868\u793a\u6ca1\u6709\u6301\u6709\uff09\u3002\u7136\u540e\u6211\u4eec\u7528\u4e00\u4e2a\u4e09\u7ef4\u6570\u7ec4\u5c31\u53ef\u4ee5\u88c5\u4e0b\u8fd9\u51e0\u79cd\u72b6\u6001\u7684\u5168\u90e8\u7ec4\u5408\uff1a
    dp[i][k][0 or 1]
    0 <= i <= n-1, 1 <= k <= K
    n \u4e3a\u5929\u6570\uff0c\u5927 K \u4e3a\u6700\u591a\u4ea4\u6613\u6570
    \u6b64\u95ee\u9898\u5171 n \u00d7 K \u00d7 2 \u79cd\u72b6\u6001\uff0c\u5168\u90e8\u7a77\u4e3e\u5c31\u80fd\u641e\u5b9a\u3002<\/p>\n

    for 0 <= i < n:
    for 1 <= k <= K:
    for s in {0, 1}:
    dp[i][k][s] = max(buy, sell, rest)
    \u800c\u4e14\u6211\u4eec\u53ef\u4ee5\u7528\u81ea\u7136\u8bed\u8a00\u63cf\u8ff0\u51fa\u6bcf\u4e00\u4e2a\u72b6\u6001\u7684\u542b\u4e49\uff0c\u6bd4\u5982\u8bf4 dp[3][2][1] \u7684\u542b\u4e49\u5c31\u662f\uff1a\u4eca\u5929\u662f\u7b2c\u4e09\u5929\uff0c\u6211\u73b0\u5728\u624b\u4e0a\u6301\u6709\u7740\u80a1\u7968\uff0c\u81f3\u4eca\u6700\u591a\u8fdb\u884c 2 \u6b21\u4ea4\u6613\u3002\u518d\u6bd4\u5982 dp[2][3][0] \u7684\u542b\u4e49\uff1a\u4eca\u5929\u662f\u7b2c\u4e8c\u5929\uff0c\u6211\u73b0\u5728\u624b\u4e0a\u6ca1\u6709\u6301\u6709\u80a1\u7968\uff0c\u81f3\u4eca\u6700\u591a\u8fdb\u884c 3 \u6b21\u4ea4\u6613\u3002<\/p>\n

    \u6211\u4eec\u60f3\u6c42\u7684\u6700\u7ec8\u7b54\u6848\u662f dp[n – 1][K][0]\uff0c\u5373\u6700\u540e\u4e00\u5929\uff0c\u6700\u591a\u5141\u8bb8 K \u6b21\u4ea4\u6613\uff0c\u6700\u591a\u83b7\u5f97\u591a\u5c11\u5229\u6da6\u3002\u8bfb\u8005\u53ef\u80fd\u95ee\u4e3a\u4ec0\u4e48\u4e0d\u662f dp[n – 1][K][1]\uff1f\u56e0\u4e3a [1] \u4ee3\u8868\u624b\u4e0a\u8fd8\u6301\u6709\u80a1\u7968\uff0c[0] \u8868\u793a\u624b\u4e0a\u7684\u80a1\u7968\u5df2\u7ecf\u5356\u51fa\u53bb\u4e86\uff0c\u5f88\u663e\u7136\u540e\u8005\u5f97\u5230\u7684\u5229\u6da6\u4e00\u5b9a\u5927\u4e8e\u524d\u8005\u3002<\/p>\n

    \u6211\u4eec\u6765\u5199\u4e00\u4e0b\u72b6\u6001\u8f6c\u79fb\u65b9\u7a0b\uff1a
    dp[i][k][0] = max(dp[i-1][k][0], dp[i-1][k][1] + prices[i])
    max( \u9009\u62e9 rest , \u9009\u62e9 sell )<\/p>\n

    \u89e3\u91ca\uff1a\u4eca\u5929\u6211\u6ca1\u6709\u6301\u6709\u80a1\u7968\uff0c\u6709\u4e24\u79cd\u53ef\u80fd\uff1a
    \u8981\u4e48\u662f\u6211\u6628\u5929\u5c31\u6ca1\u6709\u6301\u6709\uff0c\u7136\u540e\u4eca\u5929\u9009\u62e9 rest\uff0c\u6240\u4ee5\u6211\u4eca\u5929\u8fd8\u662f\u6ca1\u6709\u6301\u6709\uff1b
    \u8981\u4e48\u662f\u6211\u6628\u5929\u6301\u6709\u80a1\u7968\uff0c\u4f46\u662f\u4eca\u5929\u6211 sell \u4e86\uff0c\u6240\u4ee5\u6211\u4eca\u5929\u6ca1\u6709\u6301\u6709\u80a1\u7968\u4e86\u3002<\/p>\n

    dp[i][k][1] = max(dp[i-1][k][1], dp[i-1][k-1][0] – prices[i])
    max( \u9009\u62e9 rest , \u9009\u62e9 buy )<\/p>\n

    \u89e3\u91ca\uff1a\u4eca\u5929\u6211\u6301\u6709\u7740\u80a1\u7968\uff0c\u6709\u4e24\u79cd\u53ef\u80fd\uff1a
    \u8981\u4e48\u6211\u6628\u5929\u5c31\u6301\u6709\u7740\u80a1\u7968\uff0c\u7136\u540e\u4eca\u5929\u9009\u62e9 rest\uff0c\u6240\u4ee5\u6211\u4eca\u5929\u8fd8\u6301\u6709\u7740\u80a1\u7968\uff1b
    \u8981\u4e48\u6211\u6628\u5929\u672c\u6ca1\u6709\u6301\u6709\uff0c\u4f46\u4eca\u5929\u6211\u9009\u62e9 buy\uff0c\u6240\u4ee5\u4eca\u5929\u6211\u5c31\u6301\u6709\u80a1\u7968\u4e86\u3002<\/p>\n

    \u8fd9\u4e2a\u89e3\u91ca\u5e94\u8be5\u5f88\u6e05\u695a\u4e86\uff0c\u5982\u679c buy\uff0c\u5c31\u8981\u4ece\u5229\u6da6\u4e2d\u51cf\u53bb prices[i]\uff0c\u5982\u679c sell\uff0c\u5c31\u8981\u7ed9\u5229\u6da6\u589e\u52a0 prices[i]\u3002\u4eca\u5929\u7684\u6700\u5927\u5229\u6da6\u5c31\u662f\u8fd9\u4e24\u79cd\u53ef\u80fd\u9009\u62e9\u4e2d\u8f83\u5927\u7684\u90a3\u4e2a\u3002\u800c\u4e14\u6ce8\u610f k \u7684\u9650\u5236\uff0c\u6211\u4eec\u5728\u9009\u62e9 buy \u7684\u65f6\u5019\uff0c\u628a k \u51cf\u5c0f\u4e86 1\uff0c\u5f88\u597d\u7406\u89e3\u5427\uff0c\u5f53\u7136\u4f60\u4e5f\u53ef\u4ee5\u5728 sell \u7684\u65f6\u5019\u51cf 1\uff0c\u4e00\u6837\u7684\u3002<\/p>\n

    \u4e0d\u8fc7\u8fd8\u5dee\u6700\u540e\u4e00\u70b9\u70b9\uff0c\u5c31\u662f\u5b9a\u4e49 base case\uff0c\u5373\u6700\u7b80\u5355\u7684\u60c5\u51b5\u3002
    dp[-1][k][0] = 0
    \u89e3\u91ca\uff1a\u56e0\u4e3a i \u662f\u4ece 0 \u5f00\u59cb\u7684\uff0c\u6240\u4ee5 i = -1 \u610f\u5473\u7740\u8fd8\u6ca1\u6709\u5f00\u59cb\uff0c\u8fd9\u65f6\u5019\u7684\u5229\u6da6\u5f53\u7136\u662f 0 \u3002
    dp[-1][k][1] = -infinity
    \u89e3\u91ca\uff1a\u8fd8\u6ca1\u5f00\u59cb\u7684\u65f6\u5019\uff0c\u662f\u4e0d\u53ef\u80fd\u6301\u6709\u80a1\u7968\u7684\uff0c\u7528\u8d1f\u65e0\u7a77\u8868\u793a\u8fd9\u79cd\u4e0d\u53ef\u80fd\u3002
    dp[i][0][0] = 0
    \u89e3\u91ca\uff1a\u56e0\u4e3a k \u662f\u4ece 1 \u5f00\u59cb\u7684\uff0c\u6240\u4ee5 k = 0 \u610f\u5473\u7740\u6839\u672c\u4e0d\u5141\u8bb8\u4ea4\u6613\uff0c\u8fd9\u65f6\u5019\u5229\u6da6\u5f53\u7136\u662f 0 \u3002
    dp[i][0][1] = -infinity
    \u89e3\u91ca\uff1a\u4e0d\u5141\u8bb8\u4ea4\u6613\u7684\u60c5\u51b5\u4e0b\uff0c\u662f\u4e0d\u53ef\u80fd\u6301\u6709\u80a1\u7968\u7684\uff0c\u7528\u8d1f\u65e0\u7a77\u8868\u793a\u8fd9\u79cd\u4e0d\u53ef\u80fd\u3002<\/p>\n

    \u628a\u4e0a\u9762\u7684\u72b6\u6001\u8f6c\u79fb\u65b9\u7a0b\u603b\u7ed3\u4e00\u4e0b\uff1a
    base case\uff1a
    dp[-1][k][0] = dp[i][0][0] = 0
    dp[-1][k][1] = dp[i][0][1] = -infinity<\/p>\n

    \u72b6\u6001\u8f6c\u79fb\u65b9\u7a0b\uff1a
    dp[i][k][0] = max(dp[i-1][k][0], dp[i-1][k][1] + prices[i])
    dp[i][k][1] = max(dp[i-1][k][1], dp[i-1][k-1][0] – prices[i])
    \u8bfb\u8005\u53ef\u80fd\u4f1a\u95ee\uff0c\u8fd9\u4e2a\u6570\u7ec4\u7d22\u5f15\u662f -1 \u600e\u4e48\u7f16\u7a0b\u8868\u793a\u51fa\u6765\u5462\uff0c\u8d1f\u65e0\u7a77\u600e\u4e48\u8868\u793a\u5462\uff1f\u8fd9\u90fd\u662f\u7ec6\u8282\u95ee\u9898\uff0c\u6709\u5f88\u591a\u65b9\u6cd5\u5b9e\u73b0\u3002\u73b0\u5728\u5b8c\u6574\u7684\u6846\u67b6\u5df2\u7ecf\u5b8c\u6210\uff0c\u4e0b\u9762\u5f00\u59cb\u5177\u4f53\u5316\u3002 <\/div>\n<\/p><\/div>\n<\/li>\n

  • \n
    \n
    \n
    \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : youthes <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u7b2c\u4e00\u9898\uff0ck = 1
    \u76f4\u63a5\u5957\u72b6\u6001\u8f6c\u79fb\u65b9\u7a0b\uff0c\u6839\u636e base case\uff0c\u53ef\u4ee5\u505a\u4e00\u4e9b\u5316\u7b80\uff1a
    dp[i][1][0] = max(dp[i-1][1][0], dp[i-1][1][1] + prices[i])
    dp[i][1][1] = max(dp[i-1][1][1], dp[i-1][0][0] – prices[i])
    = max(dp[i-1][1][1], -prices[i])
    \u89e3\u91ca\uff1ak = 0 \u7684 base case\uff0c\u6240\u4ee5 dp[i-1][0][0] = 0 \u3002<\/p>\n

    \u73b0\u5728\u53d1\u73b0 k \u90fd\u662f 1\uff0c\u4e0d\u4f1a\u6539\u53d8\uff0c\u5373 k \u5bf9\u72b6\u6001\u8f6c\u79fb\u5df2\u7ecf\u6ca1\u6709\u5f71\u54cd\u4e86\u3002
    \u53ef\u4ee5\u8fdb\u884c\u8fdb\u4e00\u6b65\u5316\u7b80\u53bb\u6389\u6240\u6709 k\uff1a
    dp[i][0] = max(dp[i-1][0], dp[i-1][1] + prices[i])
    dp[i][1] = max(dp[i-1][1], -prices[i])
    \u76f4\u63a5\u5199\u51fa\u4ee3\u7801\uff1a
    int n = prices.length;
    int[][] dp = new int[n][2];
    for (int i = 0; i < n; i++) {
    dp[i][0] = Math.max(dp[i-1][0], dp[i-1][1] + prices[i]);
    dp[i][1] = Math.max(dp[i-1][1], -prices[i]);
    }
    return dp[n – 1][0];
    \u663e\u7136 i = 0 \u65f6 dp[i-1] \u662f\u4e0d\u5408\u6cd5\u7684\u3002\u8fd9\u662f\u56e0\u4e3a\u6211\u4eec\u6ca1\u6709\u5bf9 i \u7684 base case \u8fdb\u884c\u5904\u7406\u3002\u53ef\u4ee5\u8fd9\u6837\u5904\u7406\uff1a
    for (int i = 0; i < n; i++) {
    if (i – 1 == -1) {
    dp[i][0] = 0;
    \/\/ \u89e3\u91ca\uff1a
    \/\/ dp[i][0]
    \/\/ = max(dp[-1][0], dp[-1][1] + prices[i])
    \/\/ = max(0, -infinity + prices[i]) = 0
    dp[i][1] = -prices[i];
    \/\/\u89e3\u91ca\uff1a
    \/\/ dp[i][1]
    \/\/ = max(dp[-1][1], dp[-1][0] – prices[i])
    \/\/ = max(-infinity, 0 – prices[i])
    \/\/ = -prices[i]
    continue;
    }
    dp[i][0] = Math.max(dp[i-1][0], dp[i-1][1] + prices[i]);
    dp[i][1] = Math.max(dp[i-1][1], -prices[i]);
    }
    return dp[n – 1][0];
    \u7b2c\u4e00\u9898\u5c31\u89e3\u51b3\u4e86\uff0c\u4f46\u662f\u8fd9\u6837\u5904\u7406 base case \u5f88\u9ebb\u70e6\uff0c\u800c\u4e14\u6ce8\u610f\u4e00\u4e0b\u72b6\u6001\u8f6c\u79fb\u65b9\u7a0b\uff0c\u65b0\u72b6\u6001\u53ea\u548c\u76f8\u90bb\u7684\u4e00\u4e2a\u72b6\u6001\u6709\u5173\uff0c\u5176\u5b9e\u4e0d\u7528\u6574\u4e2a dp \u6570\u7ec4\uff0c\u53ea\u9700\u8981\u4e00\u4e2a\u53d8\u91cf\u50a8\u5b58\u76f8\u90bb\u7684\u90a3\u4e2a\u72b6\u6001\u5c31\u8db3\u591f\u4e86\uff0c\u8fd9\u6837\u53ef\u4ee5\u628a\u7a7a\u95f4\u590d\u6742\u5ea6\u964d\u5230 O(1):
    \/\/ k == 1
    int maxProfit_k_1(int[] prices) {
    int n = prices.length;
    \/\/ base case: dp[-1][0] = 0, dp[-1][1] = -infinity
    int dp_i_0 = 0, dp_i_1 = Integer.MIN_VALUE;
    for (int i = 0; i < n; i++) {
    \/\/ dp[i][0] = max(dp[i-1][0], dp[i-1][1] + prices[i])
    dp_i_0 = Math.max(dp_i_0, dp_i_1 + prices[i]);
    \/\/ dp[i][1] = max(dp[i-1][1], -prices[i])
    dp_i_1 = Math.max(dp_i_1, -prices[i]);
    }
    return dp_i_0;
    }
    \u4e24\u79cd\u65b9\u5f0f\u90fd\u662f\u4e00\u6837\u7684\uff0c\u4e0d\u8fc7\u8fd9\u79cd\u7f16\u7a0b\u65b9\u6cd5\u7b80\u6d01\u5f88\u591a\u3002\u4f46\u662f\u5982\u679c\u6ca1\u6709\u524d\u9762\u72b6\u6001\u8f6c\u79fb\u65b9\u7a0b\u7684\u5f15\u5bfc\uff0c\u662f\u80af\u5b9a\u770b\u4e0d\u61c2\u7684\u3002\u540e\u7eed\u7684\u9898\u76ee\uff0c\u6211\u4e3b\u8981\u5199\u8fd9\u79cd\u7a7a\u95f4\u590d\u6742\u5ea6 O(1) \u7684\u89e3\u6cd5\u3002 <\/div>\n<\/p><\/div>\n<\/li>\n

  • \n
    \n
    \n
    \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : youthes <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u7b2c\u4e8c\u9898\uff0ck = +infinity
    \u5982\u679c k \u4e3a\u6b63\u65e0\u7a77\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u8ba4\u4e3a k \u548c k – 1 \u662f\u4e00\u6837\u7684\u3002\u53ef\u4ee5\u8fd9\u6837\u6539\u5199\u6846\u67b6\uff1a
    dp[i][k][0] = max(dp[i-1][k][0], dp[i-1][k][1] + prices[i])
    dp[i][k][1] = max(dp[i-1][k][1], dp[i-1][k-1][0] – prices[i])
    = max(dp[i-1][k][1], dp[i-1][k][0] – prices[i])<\/p>\n

    \u6211\u4eec\u53d1\u73b0\u6570\u7ec4\u4e2d\u7684 k \u5df2\u7ecf\u4e0d\u4f1a\u6539\u53d8\u4e86\uff0c\u4e5f\u5c31\u662f\u8bf4\u4e0d\u9700\u8981\u8bb0\u5f55 k \u8fd9\u4e2a\u72b6\u6001\u4e86\uff1a
    dp[i][0] = max(dp[i-1][0], dp[i-1][1] + prices[i])
    dp[i][1] = max(dp[i-1][1], dp[i-1][0] – prices[i])
    \u76f4\u63a5\u7ffb\u8bd1\u6210\u4ee3\u7801\uff1a
    int maxProfit_k_inf(int[] prices) {
    int n = prices.length;
    int dp_i_0 = 0, dp_i_1 = Integer.MIN_VALUE;
    for (int i = 0; i < n; i++) {
    int temp = dp_i_0;
    dp_i_0 = Math.max(dp_i_0, dp_i_1 + prices[i]);
    dp_i_1 = Math.max(dp_i_1, temp – prices[i]);
    }
    return dp_i_0;
    } <\/div>\n<\/p><\/div>\n<\/li>\n

  • \n
    \n
    \n
    \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : youthes <\/span> <\/div>\n
    <\/i> <\/span> <\/div>\n<\/p><\/div>\n
    \u7b2c\u4e09\u9898\uff0ck = +infinity with cooldown
    \u6bcf\u6b21 sell \u4e4b\u540e\u8981\u7b49\u4e00\u5929\u624d\u80fd\u7ee7\u7eed\u4ea4\u6613\u3002\u53ea\u8981\u628a\u8fd9\u4e2a\u7279\u70b9\u878d\u5165\u4e0a\u4e00\u9898\u7684\u72b6\u6001\u8f6c\u79fb\u65b9\u7a0b\u5373\u53ef\uff1a
    dp[i][0] = max(dp[i-1][0], dp[i-1][1] + prices[i])
    dp[i][1] = max(dp[i-1][1], dp[i-2][0] – prices[i])
    \u89e3\u91ca\uff1a\u7b2c i \u5929\u9009\u62e9 buy \u7684\u65f6\u5019\uff0c\u8981\u4ece i-2 \u7684\u72b6\u6001\u8f6c\u79fb\uff0c\u800c\u4e0d\u662f i-1 \u3002
    \u7ffb\u8bd1\u6210\u4ee3\u7801\uff1a
    int maxProfit_with_cool(int[] prices) {
    int n = prices.length;
    int dp_i_0 = 0, dp_i_1 = Integer.MIN_VALUE;
    int dp_pre_0 = 0; \/\/ \u4ee3\u8868 dp[i-2][0]
    for (int i = 0; i < n; i++) {
    int temp = dp_i_0;
    dp_i_0 = Math.max(dp_i_0, dp_i_1 + prices[i]);
    dp_i_1 = Math.max(dp_i_1, dp_pre_0 – prices[i]);
    dp_pre_0 = temp;
    }
    return dp_i_0;
    } <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n","protected":false},"excerpt":{"rendered":"

    [\u9ad8\u9891\u9898]\u9762\u8bd5\u7ecf\u5178\u9898\u76ee&#8211…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[],"tags":[],"_links":{"self":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/432027"}],"collection":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=432027"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/432027\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=432027"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=432027"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=432027"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}