Data commit

Task/Cuban-primes/C/cuban-primes-1.c

@@ -0,0 +1,112 @@
+#include <limits.h>
+#include <math.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef long long llong_t;
+struct PrimeArray {
+    llong_t *ptr;
+    size_t size;
+    size_t capacity;
+};
+
+struct PrimeArray allocate() {
+    struct PrimeArray primes;
+
+    primes.size = 0;
+    primes.capacity = 10;
+    primes.ptr = malloc(primes.capacity * sizeof(llong_t));
+
+    return primes;
+}
+
+void deallocate(struct PrimeArray *primes) {
+    free(primes->ptr);
+    primes->ptr = NULL;
+}
+
+void push_back(struct PrimeArray *primes, llong_t p) {
+    if (primes->size >= primes->capacity) {
+        size_t new_capacity = (3 * primes->capacity) / 2 + 1;
+        llong_t *temp = realloc(primes->ptr, new_capacity * sizeof(llong_t));
+        if (NULL == temp) {
+            fprintf(stderr, "Failed to reallocate the prime array.");
+            exit(1);
+        } else {
+            primes->ptr = temp;
+            primes->capacity = new_capacity;
+        }
+    }
+
+    primes->ptr[primes->size++] = p;
+}
+
+int main() {
+    const int cutOff = 200, bigUn = 100000, chunks = 50, little = bigUn / chunks;
+    struct PrimeArray primes = allocate();
+    int c = 0;
+    bool showEach = true;
+    llong_t u = 0, v = 1, i;
+
+    push_back(&primes, 3);
+    push_back(&primes, 5);
+
+    printf("The first %d cuban primes:\n", cutOff);
+    for (i = 1; i < LLONG_MAX; ++i) {
+        bool found = false;
+        llong_t mx = ceil(sqrt(v += (u += 6)));
+        llong_t j;
+
+        for (j = 0; j < primes.size; ++j) {
+            if (primes.ptr[j] > mx) {
+                break;
+            }
+            if (v % primes.ptr[j] == 0) {
+                found = true;
+                break;
+            }
+        }
+        if (!found) {
+            c += 1;
+            if (showEach) {
+                llong_t z;
+                for (z = primes.ptr[primes.size - 1] + 2; z <= v - 2; z += 2) {
+                    bool fnd = false;
+
+                    for (j = 0; j < primes.size; ++j) {
+                        if (primes.ptr[j] > mx) {
+                            break;
+                        }
+                        if (z % primes.ptr[j] == 0) {
+                            fnd = true;
+                            break;
+                        }
+                    }
+                    if (!fnd) {
+                        push_back(&primes, z);
+                    }
+                }
+                push_back(&primes, v);
+                printf("%11lld", v);
+                if (c % 10 == 0) {
+                    printf("\n");
+                }
+                if (c == cutOff) {
+                    showEach = false;
+                    printf("\nProgress to the %dth cuban prime: ", bigUn);
+                }
+            }
+            if (c % little == 0) {
+                printf(".");
+                if (c == bigUn) {
+                    break;
+                }
+            }
+        }
+    }
+    printf("\nThe %dth cuban prime is %lld\n", c, v);
+
+    deallocate(&primes);
+    return 0;
+}

Task/Cuban-primes/C/cuban-primes-2.c

@@ -0,0 +1,35 @@
+#include <gmp.h>
+#include <stdio.h>
+
+typedef unsigned long int uint;
+
+int main(void)
+{
+	mpz_t a, b;
+	mpz_init(a);
+	mpz_init(b);
+
+	int found = 0;
+	int col = 0;
+	for (uint n = 1; ; n++) {
+		mpz_ui_pow_ui(a, n, 3);
+		mpz_ui_pow_ui(b, n + 1, 3);
+		mpz_sub(a, b, a);
+
+		if (!mpz_probab_prime_p(a, 5)) continue;
+
+		if (++found <= 200) {
+			gmp_printf("%10Zu", a);
+			if (++col == 8) {
+				putchar('\n');
+				col = 0;
+			}
+		} else if (found == 100000) {
+			gmp_printf("100000th: %Zu\n", a);
+		} else if (found == 1000000) {
+			gmp_printf("1000000th: %Zu\n", a);
+			break;
+		}
+	}
+	return 0;
+}