{"id":160860,"date":"2020-09-27T11:04:18","date_gmt":"2020-09-27T03:04:18","guid":{"rendered":"http:\/\/4563.org\/?p=160860"},"modified":"2020-09-27T11:04:18","modified_gmt":"2020-09-27T03:04:18","slug":"facebook-%e9%9d%a2%e8%af%95%e9%a2%98%ef%bc%9a%e7%ac%ac%e4%b8%80%e4%b8%aa%e9%94%99%e8%af%af%e7%9a%84%e4%bb%a3%e7%a0%81%e7%89%88%e6%9c%ac","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=160860","title":{"rendered":"Facebook \u9762\u8bd5\u9898\uff1a\u7b2c\u4e00\u4e2a\u9519\u8bef\u7684\u4ee3\u7801\u7248\u672c"},"content":{"rendered":"
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Facebook \u9762\u8bd5\u9898\uff1a\u7b2c\u4e00\u4e2a\u9519\u8bef\u7684\u4ee3\u7801\u7248\u672c <\/h1>\n

<\/p>\n

\n
\u8cc7\u6df1\u5927\u4f6c : zzzrf <\/span> <\/i> 0<\/span> <\/div>\n
<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n
<\/p>\n

\u4ee3\u7801\u5e93\u7684\u7248\u672c\u53f7\u662f\u4ece 1 \u5230 n \u7684\u6574\u6570\u3002\u67d0\u4e00\u5929\uff0c\u6709\u4eba\u63d0\u4ea4\u4e86\u9519\u8bef\u7248\u672c\u7684\u4ee3\u7801\uff0c\u56e0\u6b64\u9020\u6210\u81ea\u8eab\u53ca\u4e4b\u540e\u7248\u672c\u7684\u4ee3\u7801\u5728\u5355\u5143\u6d4b\u8bd5\u4e2d\u5747\u51fa\u9519\u3002\u8bf7\u627e\u51fa\u7b2c\u4e00\u4e2a\u9519\u8bef\u7684\u7248\u672c\u53f7\u3002 \u4f60\u53ef\u4ee5\u901a\u8fc7 isBadVersion \u7684\u63a5\u53e3\u6765\u5224\u65ad\u7248\u672c\u53f7 version \u662f\u5426\u5728\u5355\u5143\u6d4b\u8bd5\u4e2d\u51fa\u9519\uff0c\u5177\u4f53\u63a5\u53e3\u8be6\u60c5\u548c\u8c03\u7528\u65b9\u6cd5\u8bf7\u89c1\u4ee3\u7801\u7684\u6ce8\u91ca\u90e8\u5206\u3002<\/p>\n

\u5728\u7ebf\u505a\u9898\u5730\u5740<\/p>\n

\u6837\u4f8b<\/h2>\n
n = 5:      isBadVersion(3) -> false     isBadVersion(5) -> true     isBadVersion(4) -> true  \u56e0\u6b64\u53ef\u4ee5\u786e\u5b9a\u7b2c\u56db\u4e2a\u7248\u672c\u662f\u7b2c\u4e00\u4e2a\u9519\u8bef\u7248\u672c\u3002 <\/code><\/pre>\n
\u7b97\u6cd5\uff1a\u4e8c\u5206<\/h2>\n
\u5047\u8bbe\u7b2c k \u4e2a\u7248\u672c\u4e3a\u7b2c\u4e00\u4e2a\u9519\u8bef\u7248\u672c\uff0c\u90a3\u4e48 1—n \u4e2a\u7248\u672c\u5206\u4e3a 1—k-1 \u4e3a\u6b63\u786e\u7248\u672c\uff0ck—n \u4e3a\u9519\u8bef\u7248\u672c\uff0c \u6211\u4eec\u9700\u8981\u4ee5\u5c3d\u91cf\u5c11\u7684\u6b21\u6570\u53bb\u627e\u5230\u8fd9\u4e2a k\uff0c\u663e\u7136\u6211\u4eec\u5982\u679c\u4e00\u4e2a\u4e2a\u627e\u8fc7\u53bb\u7684\u5e73\u5747\u590d\u6742\u5ea6\u662f O(n) \u90a3\u4e48\u6211\u4eec\u53ef\u4ee5\u8003\u8651\u7528\u4e8c\u5206\u6765\u627e\u5230\u8fd9\u4e2a k,\u4e8c\u5206\u7684\u590d\u6742\u5ea6\u4e3a O(logn)<\/p>\n
    \n
  • \u4e8c\u5206[1,n]\u8fd9\u4e2a\u533a\u95f4<\/li>\n
  • \u5224\u65ad isBadVersion \uff08 mid \uff09\n
      \n
    • \u5982\u679c\u4e3a false \u8bf4\u660e\u7b2c\u4e00\u4e2a\u9519\u8bef\u7248\u672c\u5728 mid \u7684\u53f3\u8fb9\uff0c\u4ee4 left = mid<\/li>\n
    • \u53cd\u4e4b\u5219\u5728 mid \u5de6\u8fb9\uff0c\u4ee4 right = mid<\/li>\n<\/ul>\n<\/li>\n
    • \u7f29\u5c0f\u5224\u65ad\u8303\u56f4\uff0c\u5f53 left+1>=right \u7684\u65f6\u5019\u7ed3\u675f\u4e8c\u5206<\/li>\n
    • \u6700\u540e\u518d\u6b21\u5224\u65ad\u4e0b isBadVersion \uff08 left \uff09,\u5982\u679c\u662f\u9519\u8bef\u7248\u672c\u7684\u8bdd\u8fd4\u56de left,\u53cd\u4e4b\u8fd4\u56de right<\/li>\n<\/ul>\n
      \u590d\u6742\u5ea6\u5206\u6790<\/h2>\n
        \n
      • \u65f6\u95f4\u590d\u6742\u5ea6 O(logn)\n
          \n
        • \u4e8c\u5206\u7684\u65f6\u95f4\u590d\u6742\u5ea6<\/li>\n<\/ul>\n<\/li>\n
        • \u7a7a\u95f4\u590d\u6742\u5ea6 O(1)\n
            \n
          • \u65e0\u9700\u989d\u5916\u7a7a\u95f4<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
            public class Solution {     \/**      * @param n: An integer      * @return: An integer which is the first bad version.      *\/     public int findFirstBadVersion(int n) {         int left = 1, right = n; \/\/ \u5de6\u53f3\u8fb9\u754c         while (left + 1 < right){             int mid = left + (right - left) \/ 2;             \/\/ \u5224\u65ad mid \u662f\u5426\u4e3a\u6b63\u786e\u7248\u672c\uff0c\u5982\u679c\u662f\u7684\u8bdd\uff0c\u90a3\u4e48\u8bf4\u660e\u9519\u8bef\u7248\u672c\u5728 mid \u7684\u53f3\u8fb9\uff0c\u53cd\u4e4b\u5219\u5728\u5de6\u8fb9             if (SVNRepo.isBadVersion(mid)){                 right = mid; \/\/ \u5411[left\uff0cmid]\u67e5\u627e\u9519\u8bef\u7248\u672c             }             else {                  left = mid; \/\/ \u5411[mid\uff0cright]\u67e5\u627e\u9519\u8bef\u7248\u672c             }         }         \/\/ \u6700\u540e\u5224\u65ad\u4e0b left \u662f\u5426\u662f\u9519\u8bef\u7248\u672c         if (SVNRepo.isBadVersion(left)){             return left;         }         return right;     } } <\/code><\/pre>\n
            \u66f4\u591a\u9898\u89e3\u53c2\u8003<\/p>\n<\/p><\/div>\n
             \u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (0<\/span>)        <\/div>\n
             <\/div>\n<\/p><\/div>\n<\/p><\/div>\n
              \n
            • \n","protected":false},"excerpt":{"rendered":"
              Facebook \u9762\u8bd5\u9898\uff1a\u7b2c\u4e00\u4e2a\u9519…<\/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\/160860"}],"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=160860"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/160860\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=160860"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=160860"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=160860"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}