Commit4509d34

committed

add 614

1 parent5646ae5 commit4509d34Copy full SHA for 4509d34

File tree

+33

-0

lines changed

+33

-0

lines changed

Lines changed: 1 addition & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -596,6 +596,7 @@ Your ideas/fixes/algorithms are more than welcome!`
`596`	`596`	`\|627\|[Swap Salary](https://leetcode.com/problems/swap-salary/)\|[Solution](../master/database/_627.sql)\|\|\| Easy\|`
`597`	`597`	`\|620\|[Not Boring Movies](https://leetcode.com/problems/not-boring-movies/)\|[Solution](../master/database/_620.sql)\|\|\| Easy\|`
`598`	`598`	`\|619\|[Biggest Single Number](https://leetcode.com/problems/biggest-single-number/)\|[Solution](../master/database/_619.sql)\|\|\| Easy\|`
	`599`	`+\|614\|[Second Degree Follower](https://leetcode.com/problems/second-degree-follower/)\|[Solution](../master/database/_614.sql) \| \| \| Medium \| Inner Join`
`599`	`600`	`\|613\|[Shortest Distance in a Line](https://leetcode.com/problems/shortest-distance-in-a-line/)\|[Solution](../master/database/_613.sql)\|\|\| Easy\|`
`600`	`601`	`\|612\|[Shortest Distance in a Plane](https://leetcode.com/problems/shortest-distance-in-a-plane/)\|[Solution](../master/database/_612.sql)\|\|\| Medium\|`
`601`	`602`	`\|610\|[Triangle Judgement](https://leetcode.com/problems/triangle-judgement/)\|[Solution](../master/src/main/java/com/fishercoder/solutions/_610.java)\|\|\| Easy\|`

Lines changed: 32 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,32 @@`
	`1`	`+--614. Second Degree Follower`
	`2`	`+--In facebook, there is a follow table with two columns: followee, follower.`
	`3`	`+--`
	`4`	`+--Please write a sql query to get the amount of each follower’s follower if he/she has one.`
	`5`	`+--`
	`6`	`+--For example:`
	`7`	`+--`
	`8`	`+--+-------------+------------+`
	`9`	`+--\| followee \| follower \|`
	`10`	`+--+-------------+------------+`
	`11`	`+--\| A \| B \|`
	`12`	`+--\| B \| C \|`
	`13`	`+--\| B \| D \|`
	`14`	`+--\| D \| E \|`
	`15`	`+--+-------------+------------+`
	`16`	`+--should output:`
	`17`	`+--+-------------+------------+`
	`18`	`+--\| follower \| num \|`
	`19`	`+--+-------------+------------+`
	`20`	`+--\| B \| 2 \|`
	`21`	`+--\| D \| 1 \|`
	`22`	`+--+-------------+------------+`
	`23`	`+--Explaination:`
	`24`	`+--Both B and D exist in the follower list, when as a followee, B's follower is C and D, and D's follower is E. A does not exist in follower list.`
	`25`	`+--Note:`
	`26`	`+--Followee would not follow himself/herself in all cases.`
	`27`	`+--Please display the result in follower's alphabet order.`
	`28`	`+`
	`29`	`+selectf1.follower,count(distinctf2.follower)as num`
	`30`	`+from follow f1`
	`31`	`+inner join follow f2onf1.follower=f2.followee`
	`32`	`+group byf1.follower`

Comments

(0)