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 .
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
Added by:  Abhilash I 
Date:  20070206 
Time limit:  1.419s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel Pentium G860 3GHz) 
Languages:  All except: ERL JS NODEJS PERL 6 SCM chicken VB.net 
Resource:  South western 0506 
hide comments
Lehar:
20150412 17:51:25
Damn! Finally AC! :D 

lucky:
20150329 10:56:43
O(n^2 *logn) is giving me a TLE why????? is der any better method Last edit: 20150329 10:57:10 

Noureldin Yosri:
20150311 20:51:09
O(n^2 log(n)) + optimization


Kishlay Raj:
20150201 09:42:35
3


Rajat (1307086):
20150131 01:42:23
Lot of optimization needed. 

kailash:
20150120 07:35:33
@Chandan Mittal if you have used cin and cout , try using printf and scanf 

Chandan Mittal:
20150108 23:56:49
O(n^2 * log(n)) gives TLE. But why??? :( 

ankit kumar sinha:
20150101 14:14:07
dont use long long int. gives TLE


ashish kumar:
20141229 13:55:20
wrong ans on test case 9 

Miguel Oliveira:
20140611 13:51:00
very weak test cases, it doesn't even have n up to 4000 