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
2021-10-15 13:43:23
Hi,You must be here in comment sectopn after getting so many TLES.
The reason for TLE is not your logic instead its STL. Dont use any Stl library like Map,unorderd_map,vector,lower_bound. Implement your own functions.

I got 3≈4 TLES due to STL the implement My own functions and used simple array[] and AC.
2021-05-13 20:51:42 4444
Got TLE for:
[1] unorder_map
[2] arrays with lower_bound, upper_bound

AC after using arrays and equal_range.
2020-11-20 16:54:17
Use arrays and then binary search, STL implementation gives TLE
2020-10-08 06:16:31
after this try abcdef problem on spoj
2020-09-16 09:30:15
Getting TLE only, I have used MIM + (map, unordered map with good hash fxn, binary search, C++ lower_bound & upper_bound on vector after sorting it). Still getting TLE. Anyone suggest something or any other technique.
2020-08-01 05:41:36
if you do ABCDEF problem first ...its is a piece of cake for you ...same logic;
2020-06-07 12:58:36
upper bound and lower bound can help :)
2020-06-04 14:20:26
Can anyone tell me why map.find() isn't working although its complexity is log(n) too, and why using vectors get AC but not with Map function??
2020-06-04 07:30:55
(n square)log(n) is working
2020-05-04 13:35:26
STL maps gave TLE. Use array and sort instead.
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