CalmoSoft primes: Difference between revisions
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Took 210 ms
</pre>
=={{header|Delphi}}==
{{works with|Delphi|6.0}}
{{libheader|SysUtils,StdCtrls}}
<syntaxhighlight lang="Delphi">
type TLongInfo = record
RangeStart,RangeStop: integer;
SeqStart,SeqStop: integer;
Count,Sum: integer;
end;
procedure CalmoSoftPrimes(Memo: TMemo);
{Find longest sequence of prime numbers that adds up to a prime}
var Sieve: TPrimeSieve;
var Best,Tmp: TLongInfo;
var I,Cnt: integer;
var S: string;
function GetLongest(N,Limit: integer): TLongInfo;
{Get longest sequence starting at N}
{Find longest sequence of primes whose sum is prime}
var Next,Sum,Cnt: integer;
begin
Result.Count:=1;
Result.SeqStart:=N;
Result.SeqStop:=N;
Result.Sum:=1;
Sum:=N; Next:=N;
Cnt:=1;
while true do
begin
Next:=Sieve.NextPrime(Next);
if Next>Limit then break;
Sum:=Sum+Next;
Inc(Cnt);
if IsPrime(Sum) then
begin
Result.SeqStop:=Next;
Result.Count:=Cnt;
Result.Sum:=Sum;
end;
end;
end;
function LongestRange(Start,Limit: integer): TLongInfo;
{Find longest sequence between Start and Limit}
{Start should be a prime number}
var I: integer;
begin
I:=Start;
Result.SeqStart:=0;
Result.SeqStop:=0;
Result.Count:=0;
while I<=Limit do
begin
Tmp:=GetLongest(I,Limit);
if Tmp.Count>Result.Count then Result:=Tmp;
I:=Sieve.NextPrime(I);
end;
Result.RangeStart:=Start;
Result.RangeStop:=Limit;
end;
procedure ShowSequenceHeader(Best: TLongInfo);
{Show summary of information}
begin
Memo.Lines.Add('Range: '+IntToStr(Best.RangeStart)+' '+IntToStr(Best.RangeStop));
Memo.Lines.Add('Longest Sequence: '+IntToStr(Best.Count));
Memo.Lines.Add('Sum: '+IntToStr(Best.Sum));
end;
procedure ShowSequence(Best: TLongInfo; Start,Limit: integer);
{Extract sequence info from best and display it}
var S: string;
var I,Cnt: integer;
begin
S:=''; Cnt:=0;
{if Start=0 display full range other wise}
{display from start to limit}
if Start=0 then I:=Best.SeqStart
else I:=Start;
while I<=Best.SeqStop do
begin
Inc(Cnt);
S:=S+Format('%5d',[I]);
if (Cnt mod 10)=0 then S:=S+CRLF;
if Cnt>=Limit then break;
I:=Sieve.NextPrime(I);
end;
Memo.Lines.Add(S);
end;
procedure ShowHeaderSequence(Best: TLongInfo);
{Show header and sequence}
begin
ShowSequenceHeader(Best);
ShowSequence(Best,0,high(integer));
end;
begin
Sieve:=TPrimeSieve.Create;
try
{Create enough primes to cover range}
Sieve.Intialize(1000);
{Find longest sequence in range}
Best:=LongestRange(2,100);
ShowHeaderSequence(Best);
finally Sieve.Free; end;
end;
</syntaxhighlight>
{{out}}
<pre>
Range: 2 100
Longest Sequence: 21
Sum: 953
7 11 13 17 19 23 29 31 37 41
43 47 53 59 61 67 71 73 79 83
89
Elapsed Time: 2.277 ms.
</pre>
=={{header|J}}==
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