SUMFOUR  4 values whose sum is 0
The SUM problem can be formulated as follows: given four lists A, B, C, D of integer values, compute how many quadruplet (a, b, c, d ) belongs to A x B x C x D are such that a + b + c + d = 0 . In the following, we assume that all lists have the same size n
Input
The first line of the input file contains the size of the lists n (this value can be as large as 4000). We then have n lines containing four integer values (with absolute value as large as 2^{28} ) that belong respectively to A, B, C and D .
(Edited: n <= 2500)
Output
Output should be printed on a single line.
Example
Input: 6 45 22 42 16 41 27 56 30 36 53 37 77 36 30 75 46 26 38 10 62 32 54 6 45 Output: 5
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masterchef2209:
20181017 22:57:20
unordered_map with reserve keyword got accepted


mayank_soni055:
20180929 22:51:02
Lots of optimization required:


ameyanator:
20180925 11:04:43
maps sets unordered maps nothing worked! had to write the binary search on my own!! 

abdo_allah1234:
20180904 01:45:45
how cani store integer values (with absolute value as large as 2^28 ) 

jmr99:
20180821 10:08:44
applied BS but getting WA on 9 again and again! 

laxmankr:
20180817 14:14:48
did you done in java?? if yes, then please help me out.!!


abdo_allah1234:
20180730 11:36:50
is solution using lower_bound and upper_bounds? 

ankit_btech:
20180609 20:25:29
@vengatesh15 Yeah me too!!


ayushgupta1997:
20180606 19:22:53
Should do with both HashMap and Vectors to analysise complexity 

rohitnarayan:
20180331 13:26:01
@mahabir10 answer to your question should be 8! 
Added by:  Abhilash I 
Date:  20070206 
Time limit:  1.419s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JSRHINO NODEJS PERL6 VB.NET 
Resource:  South western 0506 