Möbius function: Difference between revisions
→{{header|Factor}}
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0 -1 -1 1 0 1 -1 1 0 0 -1 -1 0 -1 1 -1 0 -1 0 -1
</pre>
=={{header|C}}==
{{trans|Java}}
<lang c>#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main() {
const int MU_MAX = 1000000;
int i, j;
int *mu;
int sqroot;
sqroot = (int)sqrt(MU_MAX);
mu = malloc((MU_MAX + 1) * sizeof(int));
for (i = 0; i < MU_MAX;i++) {
mu[i] = 1;
}
for (i = 2; i <= sqroot; i++) {
if (mu[i] == 1) {
// for each factor found, swap + and -
for (j = i; j <= MU_MAX; j += i) {
mu[j] *= -i;
}
// square factor = 0
for (j = i * i; j <= MU_MAX; j += i * i) {
mu[j] = 0;
}
}
}
for (i = 2; i <= MU_MAX; i++) {
if (mu[i] == i) {
mu[i] = 1;
} else if (mu[i] == -i) {
mu[i] = -1;
} else if (mu[i] < 0) {
mu[i] = 1;
} else if (mu[i] > 0) {
mu[i] = -1;
}
}
printf("First 199 terms of the möbius function are as follows:\n ");
for (i = 1; i < 200; i++) {
printf("%2d ", mu[i]);
if ((i + 1) % 20 == 0) {
printf("\n");
}
}
free(mu);
return 0;
}</lang>
{{out}}
<pre>First 199 terms of the m÷bius function are as follows:
1 -1 -1 0 -1 1 -1 0 0 1 -1 0 -1 1 1 0 -1 0 -1
0 1 1 -1 0 0 1 0 0 -1 -1 -1 0 1 1 1 0 -1 1 1
0 -1 -1 -1 0 0 1 -1 0 0 0 1 0 -1 0 1 0 1 1 -1
0 -1 1 0 0 1 -1 -1 0 1 -1 -1 0 -1 1 0 0 1 -1 -1
0 0 1 -1 0 1 1 1 0 -1 0 1 0 1 1 1 0 -1 0 0
0 -1 -1 -1 0 -1 1 -1 0 -1 -1 1 0 -1 -1 1 0 0 1 1
0 0 1 1 0 0 0 -1 0 1 -1 -1 0 1 1 0 0 -1 -1 -1
0 1 1 1 0 1 1 0 0 -1 0 -1 0 0 -1 1 0 -1 1 1
0 1 0 -1 0 -1 1 -1 0 0 -1 0 0 -1 -1 0 0 1 1 -1
0 -1 -1 1 0 1 -1 1 0 0 -1 -1 0 -1 1 -1 0 -1 0 -1</pre>
=={{header|Factor}}==
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