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
masterchef2209: 2018-10-17 22:57:20

unordered_map with reserve keyword got accepted

very frustating question

takeaway from this question: unordered_map is significantly faster than map and use of 'reserve' can optimize it further

Last edit: 2018-10-17 23:09:17
mayank_soni055: 2018-09-29 22:51:02

Lots of optimization required:-
- don't use set in cpp
- don't use fast_io
- don't use long long int
- use equal_range instead of upper_bound and lower_bound

Last edit: 2018-09-30 12:15:25
ameyanator: 2018-09-25 11:04:43

maps sets unordered maps nothing worked! had to write the binary search on my own!!

abdo_allah1234: 2018-09-04 01:45:45

how cani store integer values (with absolute value as large as 2^28 )

jmr99: 2018-08-21 10:08:44

applied BS but getting WA on 9 again and again!

laxmankr: 2018-08-17 14:14:48

did you done in java?? if yes, then please help me out.!!

abdo_allah1234: 2018-07-30 11:36:50

is solution using lower_bound and upper_bounds?

ankit_btech: 2018-06-09 20:25:29

@vengatesh15 Yeah me too!!

ayushgupta1997: 2018-06-06 19:22:53

Should do with both Hash-Map and Vectors to analysise complexity

rohitnarayan: 2018-03-31 13:26:01

@mahabir10 answer to your question should be 8!


Added by:Abhilash I
Date:2007-02-06
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