FACEFRND - Friends of Friends

Bob uses a social networking site almost all the time. He was wondering what are Friends of Friends in that social networking site? If “X” is his friend, and “Y” is X’s friend but “Y” is not his friend, then “Y” is called his friend of friend. You have to find how many friends of friends Bob has. (Each user in that social networking site has a unique 4-digit ID number)


First line contains a integer “N” (1 <= N <= 100) the number of friends in Bob's Profile. Then follow N lines.

First Integer in each line is the ID number of Bob's friend, then an integer “M” (1 <= M <= 100) is the number of people in his friend list. Then follow M integers in that line, denoting the ID number of friends in his friend list (excluding Bob). 


Output a single integer denoting Bob's number of friends of friends.


2334 5 1256 4323 7687 3244 5678
1256 2 2334 7687
4323 5 2334 5678 6547 9766 9543


hide comments
atishya_20: 2021-06-30 11:53:13

MY 100th on spoj
AC in one go!

kumar_anubhav: 2020-06-27 13:45:08

Ac in one go!! cake piece :)

adikrmishra_1: 2020-05-19 16:42:33

AC in one go :) use STL set

jrishabh720: 2020-05-16 17:54:09

AC in one go using set :)

dylanthomas: 2020-01-26 15:16:32

for all those getting AC in one go, please send your resume to NASA. You have been selected for the next Mars mission.

cheersanimesh: 2019-10-26 23:12:39

AC in one go using map 0.00

roni_roy18: 2019-06-01 09:17:49

Very easy using set :)

masterchef2209: 2018-08-10 16:12:19

simple problem,becomes super easy with stl sets;

vkash: 2018-07-13 19:54:33

A piece of cake!!

kkislay20: 2018-06-17 14:52:02

Can be done using a single array also. Cakewalk!!

Added by:Ankit Kumar Vats
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Resource:Own Problem