Data commit

Task/M-bius-function/C/m-bius-function.c

@@ -0,0 +1,55 @@
+#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;
+}