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
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Rehas Mehar Kaur Sachdeva:
20160108 12:29:57
Can someone please give a hint how to optimise unordered_map based solution, no long long int used, n^2logn algorithm, no cin cout used..... 

cat_got_bored:
20160101 20:18:12
while doing binary search remember that the value can appear multiple times. 

cat_got_bored:
20160101 20:10:00
I couldn't get AC with STL map anyhow .... even with optimizations :(


SHIVEK SACKLECHA:
20151227 21:39:58
Dont know why but long long gives a TLE and int gives an accepted solution! Strange. 

Arjav Patel:
20151223 16:29:48
long long => tle


ranit:
20151123 08:29:36
There is a problem. I submitted the same code twice once give me TLE other give AC. It's really funny. Last edit: 20151123 08:29:55 

Lai Manh Tuan:
20151103 08:43:56
Got AC by using STL (with some optimizations).


Keshav Reddy:
20151102 22:10:45
Why does std::unordered_map give TLE? Last edit: 20151102 22:10:59 

xashru:
20151002 01:31:08
why does using


ratedx:
20150925 09:04:36
@Varun Gambhir both ordered and unordered are giving tle in my case!

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