hdu 1496 Equations

Equations

Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 5526    Accepted Submission(s): 2193

Problem Description

Consider equations having the following form:

a*x1^2+b*x2^2+c*x3^2+d*x4^2=0
a, b, c, d are integers from the interval [-50,50] and any of them cannot be 0.

It is consider a solution a system ( x1,x2,x3,x4 ) that verifies the equation, xi is an integer from [-100,100] and xi != 0, any i ∈{1,2,3,4}.

Determine how many solutions satisfy the given equation.

 

Input

The input consists of several test cases. Each test case consists of a single line containing the 4 coefficients a, b, c, d, separated by one or more blanks.
End of file.

 

Output

For each test case, output a single line containing the number of the solutions.

 

Sample Input

1 2 3 -41 1 1 1

 

Sample Output

390880

 

/*题解：

hash问题

*/

// =====================================================================================// //       Filename:  Equations.cpp//    Description:  Equations//      Algorithm:  hash+二重循环//         Status: RunTime:187ms RunMemory:8044K //        Version:  Dev-C++ 4.9.9.1 //        Created:  2014/10/9 22:32 //       Revision:  none//       Compiler:  G++//         Author:  Tip of the finger melody, [e-mail]//        Company:  none//// =====================================================================================#include<cstdio>#include<cstring>int p[10002],hash[2000002];void solve(){int a,b,c,d,i,j,sum;for(i=1; i<=100; i++)p[i] = i*i;while(scanf("%d %d %d %d",&a,&b,&c,&d)!=EOF){if((a>0&&b>0&&c>0&&d>0)||(a<0&&b<0&&c<0&&d<0)){printf("0\n");continue;}memset(hash,0,sizeof(hash));for(i=1; i<=100; i++)for(j=1; j<=100; j++)hash[p[i]*a+p[j]*b+1000000]++;for(i=1,sum=0; i<=100; i++)for(j=1; j<=100; j++)sum += hash[-(p[i]*c+p[j]*d)+1000000];printf("%d\n",sum*16);}}int main(){solve();return 0;}