hdu 1496 Equations（暴力，雜湊表 剪枝）

標籤：雜湊表   暴力   

EquationsTime Limit: 6000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 5630    Accepted Submission(s): 2237

Problem DescriptionConsider 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.
 
InputThe 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. 
OutputFor 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

 
AuthorLL 
Source“2006校園文化活動月”之“校慶杯”大學生程式設計競賽暨杭州電子科技大學第四屆大學生程式設計競賽代碼如下：

#include<stdio.h>int main(){int a,b,c,d,i,j,k,count,l,s1,s2;int pow[110];while(~scanf("%d%d%d%d",&a,&b,&c,&d)){count=0;for(i=1;i<101;++i)pow[i]=i*i;if(a>0&&b>0&&c>0&&d>0||a<0&&b<0&&c<0&&d<0){printf("0\n");continue;}for(i=1;i<101;++i){for(j=1;j<101;++j){s1=a*pow[i]+b*pow[j];if(s1>0&&c>0&&d>0||s1<0&&c<0&&d<0)continue;for(k=1;k<101;++k){s2=s1+c*pow[k];if(s2%d==0){s2/=-d;if(s2>0){for(l=1;l<101;++l){if(s2==pow[l]){count++;break;}}}}}}}printf("%d\n",count*16);}return 0;}

 

hdu 1496 Equations（暴力，雜湊表 剪枝）