MongoDB Index

 explain is used to understand execution detail In this case,"totalDocsExamined" : 1380558: shows "query by username" is quite insufficient db.users.fin...

MongoDB 索引

 explain 用來了解執行細節 在這個例子中，"totalDocsExamined" : 1380558：顯示「用 username 查詢」效率非常差 db.users.find({"username": "user101"}).explain("executionStats")> db.us...

Query MongoDB

  <div>specify returned attributes</div><div><div>// find all with all attributes</div><div>> db.users.find().pre...

查詢 MongoDB

  <div>指定回傳的屬性</div><div><div>// find all with all attributes</div><div>> db.users.find().pretty()</div><...

MongoDB more Update

MongoDB 更多更新操作

Start MongoDB & Shell CRUD

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MongoDB 入門與 Shell CRUD 操作

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leetcode easy - Contains Duplicate

 LeetCode

LeetCode Easy - 包含重複元素

 LeetCode

leetcode easy - Pascal’s Triangle

LeetCode https://leetcode.com/problems/pascals-triangle/ Code

LeetCode Easy - Pascal’s Triangle（巴斯卡三角形）

LeetCode https://leetcode.com/problems/pascals-triangle/ 程式碼

leetcode medium - Number of Islands

 Leetcode

LeetCode Medium - 島嶼數量

 LeetCode

leetcode medium - LRU Cache

LeetCode https://leetcode.com/problems/lru-cache/ Code It will be great to implement LinkedList by myself, I use JDK LinkedList directly

LeetCode 中等題 - LRU Cache

LeetCode https://leetcode.com/problems/lru-cache/ 程式碼 自己實作 LinkedList 會更好，這邊直接用 JDK 的 LinkedList

java.lang.ref

https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/ref/package-summary.html https://dzone.com/articles/weak-soft-and-phantom-references-i...

java.lang.ref 參考型別

https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/ref/package-summary.html https://dzone.com/articles/weak-soft-and-phantom-references-i...

LeetCode - Kids With the Greatest Number of Candies

  <div>LeetCode</div><div>https://leetcode.com/problems/kids-with-the-greatest-number-of-candies/submissions/</div><div>&l...

LeetCode - 擁有最多糖果的小孩

  <div>LeetCode</div><div>https://leetcode.com/problems/kids-with-the-greatest-number-of-candies/submissions/</div><div>&l...