用回朔法实现０－１背包问题，其实排序部分用的是快速排序，以提高运行的时间效率．-Schomburg method used to achieve 0-1 knapsack problem, in fact some sort of rapid, in order to increase the efficiency of operations.
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001396s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.064636s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001070s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001159s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.000978s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003093s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.000823s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003653s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.012878s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001195s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 67555 [ RunTime:0.022356s ]
