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assuming a!=0, you could cut it to O(n^2) by solving for na given nb and nc. 

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assuming a!=0, you could cut it to O(n^2) by solving for na given nb and nc.


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thank you very much. 
i don't have enough words to tell you how much you helped me. 
merry christmas 

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thank you very much.
i don't have enough words to tell you how much you helped me.
merry christmas


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<div class="content wysiwyg-content">
 
i'm a student and my current project is to write an efficient program that reads 5 complete numbers 
a,b,c,d,e,n 
for that type of equation: 
aX + bY +cZ = d 
input - 5 complete numbers 
output - the number of solutions to the equation &nbsp;between 
n and -n 
according to my program i have n^3 possibilities and i'm looking for a more efficient alogorithm. 
here is what i did: 
 
#include &lt;iostream.h&gt; 
 
void main () 
{ 
&nbsp;cout&lt;&lt;&quot;please enter 5 complete numbers&quot;&lt;&lt;'\n'; 
&nbsp;int a,b,c; 
&nbsp;int d; 
&nbsp;int n; 
&nbsp;int solution = 0; 
&nbsp;int na; 
&nbsp;int nb; 
&nbsp;int nc; 
&nbsp;int num_of_solutions = 0; 
&nbsp;int counter = 0; 
 
&nbsp;cin&gt;&gt;a&gt;&gt;b&gt;&gt;c&gt;&gt;d&gt;&gt;n; 
 
&nbsp;na = (-1)*n; 
&nbsp;nb = (-1)*n; 
&nbsp;nc = (-1)*n; 
 
&nbsp;while (nc &lt;= n){ 
&nbsp; solution = a*na + b*nb + c*nc; 
&nbsp; if (solution == d) 
&nbsp; &nbsp;num_of_sol ++; 
&nbsp; na ++; 
&nbsp; if (na == n+1){ 
&nbsp; &nbsp;nb ++; 
&nbsp; &nbsp;na = -n; 
&nbsp; } 
&nbsp; if (nb == n+1){ 
&nbsp; &nbsp;nc ++; 
&nbsp; &nbsp;nb = -n; 
&nbsp; } 
&nbsp; counter ++; 
&nbsp; 
&nbsp;} 
&nbsp;cout&lt;&lt;num_of_sol&lt;&lt;'\n'&lt;&lt;counter&lt;&lt;'\n'; 
} 
&nbsp; 
 
merry christmess to you all. 
&nbsp; 
</div>
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i'm a student and my current project is to write an efficient program that reads 5 complete numbers 
a,b,c,d,e,n 
for that type of equation: 
aX + bY +cZ = d 
input - 5 complete numbers 
output - the number of solutions to the equation between 
n and -n 
according to my program i have n^3 possibilities and i'm looking for a more efficient alogorithm. 
here is what i did: 

#include <iostream.h> 

void main () 
{ 
 cout<<"please enter 5 complete numbers"<<'\n'; 
 int a,b,c; 
 int d; 
 int n; 
 int solution = 0; 
 int na; 
 int nb; 
 int nc; 
 int num_of_solutions = 0; 
 int counter = 0; 

 cin>>a>>b>>c>>d>>n; 

 na = (-1)*n; 
 nb = (-1)*n; 
 nc = (-1)*n; 

 while (nc <= n){ 
 solution = a*na + b*nb + c*nc; 
 if (solution == d) 
 num_of_sol ++; 
 na ++; 
 if (na == n+1){ 
 nb ++; 
 na = -n; 
 } 
 if (nb == n+1){ 
 nc ++; 
 nb = -n; 
 } 
 counter ++; 
 
 } 
 cout<<num_of_sol<<'\n'<<counter<<'\n'; 
} 
 

merry christmess to you all.

a smart alogorithm needed

C++ is an intermediate-level general-purpose programming language, not to be confused with C or C#. It was developed as a set of extensions to the C programming language to improve type-safety and add support for automatic resource management, object-orientation, generic programming, and exception handling, among other features.