poj27854 Values whose Sum is 0
http://poj.org/problem?id=2785
4 Values whose Sum is 0
| Time Limit: 15000MS | Memory Limit: 228000K | |
| Total Submissions: 28927 | Accepted: 8753 | |
| Case Time Limit: 5000MS | ||
Description
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 .
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 .
Output
For each input file, your program has to write the number quadruplets whose sum is zero.
Sample 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
Sample Output
5
Hint
Sample Explanation: Indeed, the sum of the five following quadruplets is zero: (-45, -27, 42, 30), (26, 30, -10, -46), (-32, 22, 56, -46),(-32, 30, -75, 77), (-32, -54, 56, 30).
Source
Southwestern Europe 2005
四个数的和为0完全可以转化为两个数的和为0，用二分法，注意一个数可能与多个数的和为0，这时候二分不能找到就return1；
#include
#include
#define maxn 4002
using namespace std;
int a[maxn];
int b[maxn];
int c[maxn];
int d[maxn];
int q[maxn*maxn];
int q1[maxn*maxn];
int sum=0;
int quick(int ans,int k)
{
int l=0,r=k-1;
while(l>n;
for(int i=0;i>a[i]>>b[i]>>c[i]>>d[i];
int k=0;int k1=0;
for(int i=0;i