{"id":92225,"date":"2020-05-15T10:04:22","date_gmt":"2020-05-15T02:04:22","guid":{"rendered":"http:\/\/4563.org\/?p=92225"},"modified":"2020-05-15T10:04:22","modified_gmt":"2020-05-15T02:04:22","slug":"%e8%8f%9c%e9%b8%9f%e5%86%99%e4%ba%86%e4%b8%80%e4%b8%aa%e6%8e%92%e5%88%97%e7%bb%84%e5%90%88%e7%ae%97%e6%b3%95%ef%bc%8c%e4%b8%8d%e7%94%a8%e9%80%92%e5%bd%92%e4%b8%bb%e8%a6%81%e4%b8%8d%e7%94%a8%e5%88%b0","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=92225","title":{"rendered":"\u83dc\u9e1f\u5199\u4e86\u4e00\u4e2a\u6392\u5217\u7ec4\u5408\u7b97\u6cd5\uff0c\u4e0d\u7528\u9012\u5f52;\u4e3b\u8981\u4e0d\u7528\u5230\u4ea4\u6362"},"content":{"rendered":"<div>\n<div>\n<div>\n<h1>                  \u83dc\u9e1f\u5199\u4e86\u4e00\u4e2a\u6392\u5217\u7ec4\u5408\u7b97\u6cd5\uff0c\u4e0d\u7528\u9012\u5f52;\u4e3b\u8981\u4e0d\u7528\u5230\u4ea4\u6362               <\/h1>\n<p> <\/p>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : crella <\/span>  <span><i><\/i> 17<\/span> <\/div>\n<div> <\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<div isfirst=\"1\">                        \u83dc\u9e1f\u5199\u4e86\u4e00\u4e2a\u6392\u5217\u7ec4\u5408\u7b97\u6cd5\uff0c\u4e0d\u7528\u9012\u5f52;\u4e3b\u8981\u4e0d\u7528\u5230\u4ea4\u6362\uff1b\u4e3b\u8981\u662f\u5229\u7528 \u6570\u7ec4\u7684\u8865\u96c6\u6570\u7ec4\u7684\u6700\u503c\u3002<\/p>\n<p>\u7ec4\u5408\u6570\u6dfb\u52a0\uff1a\u6587\u6863<br \/> \u5047\u8bbe\u4e3a C(n, m)\u6a21\u5f0f\u3002\u5f53\u524d\u5217\u8868\u4e3a @list\uff0c\u521d\u59cb\u503c\u4e3a[1,2,..m]\uff0c\u6709 m \u4e2a\u5143\u7d20\u3002<\/p>\n<p> @model \u662f 1~n \u6240\u6709\u6574\u6570\u6784\u6210\u7684\u6570\u7ec4<br \/> delta \u6570\u7ec4\u662f @model \u51cf\u53bb @list \u7684\u6240\u6709\u5143\u7d20\u3002<br \/>[email&#160;protected] \u4ece\u540e\u5f80\u524d\u627e\u5230\u7b2c\u4e00\u4e2a\u5143\u7d20 A\uff0c\u5176\u4f4d\u7f6e\u4e3a ji\uff0c\u4f7f\u5f97 A&lt;delta \u6570\u7ec4\u5185\u7684\u6700\u5927\u503c B(\u5e94\u8be5\u662f delta \u6570\u7ec4\u7684\u6700\u540e\u4e00\u4f4d)<\/p>\n<p>&#8230;\u82e5\u5b58\u5728 B\uff0c\u5219\u627e\u51fa delta \u6570\u7ec4\u5185\u6240\u6709\u6bd4 A \u5927\u7684\u5143\u7d20\u96c6\u5408\u4e2d\u7684\u6700\u5c0f\u503c C \u3002<br \/>&#8230;\u628a @list \u7684 ji \u4f4d\u7f6e\u66ff\u6362\u4e3a C \u5143\u7d20\u3002<br \/>&#8230;\u5bf9\u4e8e\u66f4\u65b0\u540e\u7684 @list \u4ece\u4f4d\u7f6e 0 \u5230 ji \u7684\u5b50\u96c6 D\uff0c\u83b7\u53d6 @model-D \u7684\u6570\u7ec4\u4e2d\u6240\u6709\u5927\u4e8e C \u7684\u5143\u7d20\u7ec4\u6210\u7684\u96c6\u5408 E \u3002<br \/>&#8230;&#8230;\u5982\u679c E \u4e3a\u7a7a\uff0c\u5219 @list \u4ece ji \u5230(m-1)\u4f4d\u7f6e\u4e0a\u6240\u6709\u7684\u6570\u662f n \u3001n-1 \u3001n-2 &#8230;\uff0c\u6b64\u65f6 @list \u7b26\u5408\u6761\u4ef6\u3002\u76f4\u63a5\u8df3\u51fa\u6d41\u7a0b<br \/>&#8230;&#8230;\u5982\u679c E \u4e0d\u4e3a\u7a7a\uff0c\u5219\u628a @list \u4ece(ji+1)\u5230(m-1)\u4f4d\u7f6e\uff0c\u4f9d\u6b21\u8bbe\u4e3a E[0]\u3001E[1]..\u3002<\/p>\n<p>&#8230;&#8230;\u82e5\u4e0d\u5b58\u5728 B\uff0c \u5219\u7ee7\u7eed\u4ece\u540e\u5f80\u524d\u627e\u5230\u5bf9\u5e94\u7684\u5143\u7d20 A<\/p>\n<p>&#8230;\u5982\u679c\u6574\u4e2a @list \u90fd\u627e\u4e0d\u5230\u7b26\u5408\u6761\u4ef6\u7684 A\uff0c\u5219 @list \u5df2\u662f\u672c\u6b21\u7ec4\u5408\u4e2d\u7684\u6700\u5927\u5012\u5e8f\u6392\u5217: [n, n-1, n-2 &#8230;]\u3002\u76f4\u63a5\u8df3\u51fa\u6d41\u7a0b<\/p>\n<p>\u60c5\u666f\u662f\u7528\u8001\u65b9\u6cd5\u751f\u6210 8 nPr 8 \u65f6\uff0c\u5df2\u7ecf\u6709 4 \u4e07\u4e2a\u96c6\u5408\u4e86\uff0c\u5982\u679c n \u548c m \u518d\u5927\u4e00\u70b9\uff0cruby \u80af\u5b9a\u8981\u7206\u5185\u5b58\u4e86\u3002\u4e8e\u662f\u60f3\u501f\u7528 ruby \u7684\u8fed\u4ee3\u5668\u6765\u5b9e\u73b0\u5faa\u73af\uff1b\u4e8e\u662f\u5c31\u8981\u6839\u636e\u5f53\u524d\u7684\u6392\u5217\u6570\u7ec4\u751f\u6210\u4e0b\u4e00\u6b65\u7684\u6392\u5217\u6570\u7ec4\uff0c\uff08\u7ec4\u5408\u6570\u7ec4\u7684\u64cd\u4f5c\u540c\u7406\uff09\u3002<\/p>\n<p>\u770b\u4e86\u4e00\u4e0b\u767e\u5ea6\u524d\u51e0\u9875\uff0c\u8981\u4e48\u9012\u5f52\uff0c\u8981\u4e48\u4ea4\u6362\u3002\u9012\u5f52\u8fd9\u4e2a\u56e0\u4e3a ruby \u6027\u80fd\u95ee\u9898\u6240\u4ee5\u6211\u4e0d\u80fd\u7528\uff0c\u4ea4\u6362\u8fd9\u4e2a\u6211\u60f3\u4e86\u4e00\u4e0b\uff0c\u611f\u89c9\u6ca1\u6211\u73b0\u5728\u8fd9\u4e2a\u7b97\u6cd5\u5199\u7740\u8212\u670d\u3002<\/p>\n<p>\u73b0\u5728\u8fd9\u4e2a\u7b97\u6cd5\u4e0d\u5360\u5185\u5b58\uff0c\u4f46\u662f\u901f\u5ea6\u6bd4\u8f83\u7740\u6025\uff0c\u7528 ruby-prof \u770b\u51fa\u6765\u662f\u5728 \u83b7\u53d6\u5f53\u524d\u6392\u5217\u6570\u7ec4\u7684\u8865\u96c6\u6570\u7ec4 \u7684\u5faa\u73af\u91cc\u9762\u8f83\u6162\uff1b\u6682\u65f6\u6ca1\u60f3\u5230\u600e\u4e48\u89e3\u51b3\u3002<\/p>\n<p>\u81f3\u4e8e\u628a\u8fd9\u4e2a\u7c7b\u8f6c\u5316\u6210 ruby \u8fed\u4ee3\u5668\uff0c\u4e00\u65f6\u5fd8\u8bb0 Enumerable \u548c.each()\u662f\u8981\u600e\u4e48\u5199\u7684\u4e86\uff0c\u8fd8\u8981\u518d\u641c\u4e00\u4e0b\u4ee3\u7801\uff0c\u54c8\u54c8\u3002<\/p>\n<p>\u83dc\u9e1f\u4e00\u679a\uff0c\u6c42\u8f7b\u62cd\u3002\u5730\u5740\u662f https:\/\/gitee.com\/crella\/sanla\/blob\/master\/permlist.rb      <\/p><\/div>\n<div> <b>\u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (<span>1<\/span>)        <\/div>\n<div> <\/div>\n<\/p><\/div>\n<\/p><\/div>\n<ul>\n<li data-pid=\"1243376\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u4e3b<\/span> <span>\u8cc7\u6df1\u5927\u4f6c : crella <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u4f7f\u7528\u65b9\u6cd5\u89c1\u540c\u4e00\u4ed3\u5e93\u4e0b\u7684 list-test.rb                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li>\n","protected":false},"excerpt":{"rendered":"<p>\u83dc\u9e1f\u5199\u4e86\u4e00\u4e2a\u6392\u5217\u7ec4\u5408\u7b97\u6cd5\uff0c\u4e0d\u7528\u9012\u5f52&hellip;<\/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\/92225"}],"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=92225"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/92225\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=92225"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=92225"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=92225"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}