4 Values whose Sum is 0

Question

题目描述
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 ) ∈ 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 .
输入
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 .
输出
For each input file, your program has to write the number quadruplets whose sum is zero.
样例输入
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
样例输出
5

Answer 1

http://blog.csdn.net/lvshubao1314/article/details/19756437