竹蜻蜓飞行的博客

要注意边界！细节是魔鬼！class Solution { public int[] searchRange(int[] nums, int target) { int[] res = new int[]{-1, -1}; res[0] = findLeftBound(nums, target); res[1] = findRightBound(nums, target); return res; } pub.

class Solution { public List<List<Integer>> permute(int[] nums) { //结果集合 List<List<Integer>> res = new ArrayList<>(); //visited是标记作用 int[] visited = new int[nums.length]; //new Arra.

（31）511. 游戏玩法分析 Iselect player_id,min(event_date) as first_loginfrom activitygroup by player_id（32）512. 游戏玩法分析 IIselect a.player_id,a.device_id from activity ajoin (select player_id,min(event_date) as first_login from activity group by player_id)

（21）1517. 查找拥有有效邮箱的用户正则表达式的使用，令人脑大。select *from users where mail regexp '^[a-zA-A]+[a-zA-Z0-9_\\./\\-]*@leetcode\\.com$';（22）584. 寻找用户推荐人select name from customer where referee_id<>2 or referee_id is null;（23）1571. 仓库经理select w.nam

（1） 1068. 产品销售分析 Iselect p.product_name,s.year,s.pricefrom sales sjoin product pon s.product_id=p.product_id;（2）1069. 产品销售分析 IIselect product_id,sum(quantity) as total_quantityfrom salesgroup by product_id;（3）107