每周至少做一个leetcode 的算法题
https://leetcode-cn.com/problems/merge-intervals/
观察后发现,可以先排序,然后再遍历一遍,即可得到结果。
遍历时,发现下一个节点左边界在当前小区域中,则拓展右边界;否则,更新当前小区域为下一个节点区域。
阅读并点评至少一篇英文技术文章
TODO
学习至少一个技术技巧
一般手机号是纯数字的,用字符串形式存在数据库中。
如果对手机号做了索引,那么查询时必须是字符串形式才能命中索引。
体会一下:
mysql> explain select phone from my_user where phone = 18000000000;
+----+-------------+-------------+-------+----------------------+----------------------+---------+------+--------+--------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------------+-------+----------------------+----------------------+---------+------+--------+--------------------------+
| 1 | SIMPLE | my_user | index | my_user_2277d84b | my_user_2277d84b | 162 | NULL | 116593 | Using where; Using index |
+----+-------------+-------------+-------+----------------------+----------------------+---------+------+--------+--------------------------+
1 row in set (0.00 sec)
mysql> explain select phone from my_user where phone = '18000000000';
+----+-------------+-------------+------+----------------------+----------------------+---------+-------+------+--------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------------+------+----------------------+----------------------+---------+-------+------+--------------------------+
| 1 | SIMPLE | my_user | ref | my_user_2277d84b | my_user_2277d84b | 162 | const | 1 | Using where; Using index |
+----+-------------+-------------+------+----------------------+----------------------+---------+-------+------+--------------------------+
1 row in set (0.00 sec)
至少分享一篇有观点和思考的技术文章
https://mp.weixin.qq.com/s/q05Df_TKWUSlhK6V6KTrfw
优秀工程师必备的一项技能,你解锁了吗?