Data commit

Task/Pierpont-primes/C/pierpont-primes.c

@@ -0,0 +1,124 @@
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+const int PRIMES[] = {
+      2,   3,   5,   7,  11,  13,  17,  19,  23,  29,  31,  37,  41,  43,  47,
+     53,  59,  61,  67,  71,  73,  79,  83,  89,  97, 101, 103, 107, 109, 113,
+    127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197,
+    199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281,
+    283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379,
+    383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463,
+    467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571,
+    577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659,
+    661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761,
+    769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863,
+    877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977,
+};
+#define PRIME_SIZE (sizeof(PRIMES) / sizeof(int))
+
+bool isPrime(const int n) {
+    int i;
+
+    if (n < 2) {
+        return false;
+    }
+
+    for (i = 0; i < PRIME_SIZE; i++) {
+        if (n == PRIMES[i]) {
+            return true;
+        }
+        if (n % PRIMES[i] == 0) {
+            return false;
+        }
+    }
+
+    if (n < PRIMES[PRIME_SIZE - 1] * PRIMES[PRIME_SIZE - 1]) {
+        return true;
+    }
+
+    i = PRIMES[PRIME_SIZE - 1]+2;
+    while (i * i < n) {
+        if (n % i == 0) {
+            return false;
+        }
+        i += 2;
+    }
+
+    return true;
+}
+
+#define N 50
+int p[2][50];
+void pierpont() {
+    int64_t s[8 * N];
+    int count = 0;
+    int count1 = 1;
+    int count2 = 0;
+    int i2 = 0;
+    int i3 = 0;
+    int k = 1;
+    int64_t n2, n3, t;
+    int64_t *sp = &s[1];
+
+    memset(p[0], 0, N * sizeof(int));
+    memset(p[1], 0, N * sizeof(int));
+    p[0][0] = 2;
+    s[0] = 1;
+
+    while (count < N) {
+        n2 = s[i2] * 2;
+        n3 = s[i3] * 3;
+        if (n2 < n3) {
+            t = n2;
+            i2++;
+        } else {
+            t = n3;
+            i3++;
+        }
+        if (t > s[k - 1]) {
+            *sp++ = t;
+            k++;
+
+            t++;
+            if (count1 < N && isPrime(t)) {
+                p[0][count1] = t;
+                count1++;
+            }
+
+            t -= 2;
+            if (count2 < N && isPrime(t)) {
+                p[1][count2] = t;
+                count2++;
+            }
+
+            count = min(count1, count2);
+        }
+    }
+}
+
+int main() {
+    int i;
+
+    pierpont();
+
+    printf("First 50 Pierpont primes of the first kind:\n");
+    for (i = 0; i < N; i++) {
+        printf("%8d ", p[0][i]);
+        if ((i - 9) % 10 == 0) {
+            printf("\n");
+        }
+    }
+    printf("\n");
+
+    printf("First 50 Pierpont primes of the second kind:\n");
+    for (i = 0; i < N; i++) {
+        printf("%8d ", p[1][i]);
+        if ((i - 9) % 10 == 0) {
+            printf("\n");
+        }
+    }
+    printf("\n");
+}