Product of min and max prime factors: Difference between revisions
Product of min and max prime factors (view source)
Revision as of 07:22, 30 October 2022
, 1 year agoAdd C
Not a robot (talk | contribs) (Add Draco) |
Not a robot (talk | contribs) (Add C) |
||
Line 89:
9 82 6889 14 85 86 87 22 7921 10
91 46 93 94 95 6 9409 14 33 10</pre>
=={{header|C}}==
<syntaxhighlight lang="c">#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#define MAX 100
void sieve(bool *prime, int max) {
memset(prime, true, max+1);
prime[0] = prime[1] = false;
for (int p=2; p*p<=max; p++)
for (int c=p*p; c<=max; c+=p)
prime[c] = false;
}
int lo_fac(bool *prime, int n) {
if (n==1) return 1;
for (int f=2; f<=n; f++)
if (prime[f] && n%f == 0) return f;
return n;
}
int hi_fac(bool *prime, int n) {
if (n==1) return 1;
for (int f=n; f>=2; f--)
if (prime[f] && n%f == 0) return f;
return n;
}
int main() {
bool prime[MAX+1];
sieve(prime, MAX);
for (int i=1; i<=MAX; i++) {
printf("%6d", lo_fac(prime, i) * hi_fac(prime, i));
if (i%10 == 0) printf("\n");
}
return 0;
}</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|C++}}==
| |||