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, 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

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

hide comments
2017-06-18 14:12:45
Using map or unordered_map didn't work for me even after the prevailing "reserved" keyword.After having tried many approaches I come to know, this problem asks to use binary search either simply or through "equal range", I think this approach would be a finer one.
2017-06-07 11:55:21
Same question as @up79, TLE without reserve(), when using unordered_map
BTW, 2.33 secs using upper_bound/lower_bound & 2.84 secs using unordered_map

Last edit: 2017-06-07 15:57:34
2017-05-24 10:47:06
sas1905 pro /\
2017-05-23 16:00:22
TLE with bounds ..AC with equal_range
2017-04-18 00:39:58
You can do it in 0.08s by using Feynman's algorithm.
2017-04-18 00:02:30
TLE with lower bound and upper bound.
A/C with equal_range and unordered_map + reserve!
2017-03-24 21:57:49
simple sorting and equal_range ...AC in one go
2017-03-18 17:22:59
its just simple.... just upper_bound and lower_bound thats it!
AC in second go ;)
2017-03-10 06:22:55


Last edit: 2017-04-24 23:33:14
2017-03-09 16:33:58
use equal_range, if you get TLE with lower and upper bound!
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