Product of min and max prime factors: Difference between revisions
Product of min and max prime factors (view source)
Revision as of 03:26, 11 October 2023
, 7 months agoThe D code for this problem
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(The D code for this problem) |
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9 82 6889 14 85 86 87 22 7921 10
91 46 93 94 95 6 9409 14 33 10</pre>
=={{header|D}}==
<syntaxhighlight lang="D">
import std.stdio : writef;
void main() {
auto sieve = sieve(100);
for(ulong i = 1; i <= 100; i++) {
writef("%4d ", min_prime_factor(i, sieve) * max_prime_factor(i, sieve));
if(i % 10 == 0)
writef("\n");
}
}
bool []sieve(ulong max) {
bool []sieve = new bool[](max + 1);
sieve[] = true;
sieve[0] = false;
sieve[1] = false;
for(ulong i = 2; i <= max; i++)
if(sieve[i])
for(ulong j = i * 2; j <= max; j += i)
sieve[j] = false;
return sieve;
}
ulong min_prime_factor(ulong number, bool []sieve) {
if (number <= 1)
return 1;
for(ulong index = 2; index <= number; index++)
if(sieve[index] && number % index == 0)
return index;
assert(0 && "Sieve was not initialized correctly");
}
ulong max_prime_factor(ulong number, bool []sieve) {
if (number <= 1)
return 1;
for(ulong index = number; index >= 2; index--)
if(sieve[index] && number % index == 0)
return index;
assert(0 && "Sieve was not initialized correctly");
}
</syntaxhighlight>
{{out}}
<pre>
1 4 9 4 25 6 49 4 9 10
121 6 169 14 15 4 289 6 361 10
21 22 529 6 25 26 9 14 841 10
961 4 33 34 35 6 1369 38 39 10
1681 14 1849 22 15 46 2209 6 49 10
51 26 2809 6 55 14 57 58 3481 10
3721 62 21 4 65 22 4489 34 69 14
5041 6 5329 74 15 38 77 26 6241 10
9 82 6889 14 85 86 87 22 7921 10
91 46 93 94 95 6 9409 14 33 10
</pre>
=={{header|Delphi}}==
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