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 VB.net 
Resource:  South western 0506 
hide comments
kobe24:
20150905 00:30:06
Last edit: 20150905 00:52:55 

earner:
20150827 18:12:06
can anyone tell why the 10th test case is giving wrong answer?


shaky99:
20150811 12:17:08
10th test case gives WA.. can any one tell why?? Last edit: 20150811 12:18:07 

Abhinandan Agarwal:
20150804 21:52:43
Use dynamic allocation of array in case you are using binary search approach. 

Bhuvnesh Jain:
20150722 21:44:57
brilliant question with even brilliant test cases. knew that qsort() is slower than sort() in worst case complexity but never had test cases which led me to change qsort to sort.... but here CAUTION: use only sort or your own implementation of merge/heap sort... do not use quick sort at all... 

Hussein Aassem:
20150708 02:00:51
a testcase must be added with all the 4000 the same number to overflow char .... check my submission Last edit: 20150708 02:02:50 

Liquid_Science:
20150701 15:48:11
Nearly Impossible in java :( 

kshitij tripathi:
20150630 14:47:43
Nice Question..don't use Long Long int !! :D 

Varun Gambhir:
20150623 21:11:15
Ordered map in c++ gives TLE and unordered gives AC(after some optimisations). Finally AC. :D Last edit: 20150623 21:11:36 

sameer makker:
20150620 18:20:15
Can anybody explain why unordered_map fails here ?
