带时间窗的车辆路径问题(Vehicle Routing Problem with Time
Windows, VRPTW)是对物流配送管理的核心问题——配送车辆调度
的问题抽象,其是在基本VRP基础上添加了时间窗约束衍生而来的,
可以将VRPTW描述为:使车辆从站点出发服务用户,完成用户需求
后仍返回站点,规定每个用户只能被一辆车服务且仅服务一次,且对
用户的服务必须在用户事先指定的时间窗内进行,问题的优化目标是
如何选择适当的路径,使得在满足以上约束条件的情况下,完成全部
需求花费的总成本最小或总利润最大。
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001009s ]
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:0.069452s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001006s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001116s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.000965s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003185s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.000915s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003694s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.023941s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001583s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 19919 [ RunTime:0.018010s ]
