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 228 ) 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

hide comments
bsaha205: 2015-06-16 22:13:57

can you tell the tenth case??
it is giving wrong ans :( :(

xxbloodysantaxx: 2015-06-08 20:48:58

Time Limit is too strict will make you cry!

kirakira: 2015-06-08 04:53:20

damn i almost cry for not AC such "easy" problem :(
Do not use long long, do not use binary search, in my case, I even cannot use STL::vector / map / set, etc.

i_am_looser: 2015-05-08 15:19:09

STL - took 5 minute to get AC : )

Lehar: 2015-04-12 17:51:25

Damn! Finally AC! :D

lucky: 2015-03-29 10:56:43

O(n^2 *logn) is giving me a TLE why????? is der any better method

Last edit: 2015-03-29 10:57:10
Noureldin Yosri: 2015-03-11 20:51:09

O(n^2 log(n)) + optimization
caution : std::map is very slow

Kishlay Raj: 2015-02-01 09:42:35

3
0 0 0 0
0 0 0 0
-1 -1 1 1

Rajat (1307086): 2015-01-31 01:42:23

Lot of optimization needed.

kailash: 2015-01-20 07:35:33

@Chandan Mittal if you have used cin and cout , try using printf and scanf


Added by:Abhilash I
Date:2007-02-06
Time limit:1.419s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ERL JS-RHINO NODEJS PERL6 VB.NET
Resource:South western 05-06