Data commit

Task/Successive-prime-differences/C/successive-prime-differences.c

@@ -0,0 +1,170 @@
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#define PRIME_COUNT 100000
+int64_t PRIMES[PRIME_COUNT];
+size_t primeSize = 0;
+
+bool isPrime(int n) {
+    size_t i = 0;
+
+    for (i = 0; i < primeSize; i++) {
+        int64_t p = PRIMES[i];
+        if (n == p) {
+            return true;
+        }
+        if (n % p == 0) {
+            return false;
+        }
+        if (p * p > n) {
+            break;
+        }
+    }
+
+    return true;
+}
+
+void initialize() {
+    int i;
+
+    PRIMES[primeSize++] = 2;
+    PRIMES[primeSize++] = 3;
+    PRIMES[primeSize++] = 5;
+    PRIMES[primeSize++] = 7;
+    PRIMES[primeSize++] = 11;
+    PRIMES[primeSize++] = 13;
+    PRIMES[primeSize++] = 17;
+    PRIMES[primeSize++] = 19;
+
+    for (i = 21; primeSize < PRIME_COUNT;) {
+        if (isPrime(i)) {
+            PRIMES[primeSize++] = i;
+        }
+        i += 2;
+
+        if (primeSize < PRIME_COUNT && isPrime(i)) {
+            PRIMES[primeSize++] = i;
+        }
+        i += 2;
+    }
+}
+
+void diff1(size_t diff) {
+    int64_t pm0, pm1;
+    int64_t fg1 = 0, fg2 = 0, lg1 = 0, lg2 = 0;
+    size_t pos, count = 0;
+
+    if (diff == 0) {
+        return;
+    }
+
+    pm0 = PRIMES[0];
+    for (pos = 1; pos < PRIME_COUNT; pos++) {
+        pm1 = pm0;
+        pm0 = PRIMES[pos];
+        if (pm0 > 1000000) {
+            break;
+        }
+        if (pm0 - pm1 == diff) {
+            count++;
+            if (fg1 == 0) {
+                fg1 = pm1;
+                fg2 = pm0;
+            }
+            lg1 = pm1;
+            lg2 = pm0;
+        }
+    }
+
+    printf("%ld|%d|%lld %lld|%lld %lld|\n", diff, count, fg1, fg2, lg1, lg2);
+}
+
+void diff2(size_t d0, size_t d1) {
+    int64_t pm0, pm1, pm2;
+    int64_t fg1 = 0, fg2, fg3, lg1, lg2, lg3;
+    size_t pos, count = 0;
+
+    if (d0 == 0 || d1 == 0) {
+        return;
+    }
+
+    pm1 = PRIMES[0];
+    pm0 = PRIMES[1];
+    for (pos = 2; pos < PRIME_COUNT; pos++) {
+        pm2 = pm1;
+        pm1 = pm0;
+        pm0 = PRIMES[pos];
+        if (pm0 > 1000000) {
+            break;
+        }
+        if (pm1 - pm2 == d0 && pm0 - pm1 == d1) {
+            count++;
+            if (fg1 == 0) {
+                fg1 = pm2;
+                fg2 = pm1;
+                fg3 = pm0;
+            }
+            lg1 = pm2;
+            lg2 = pm1;
+            lg3 = pm0;
+        }
+    }
+
+    printf("%d %d|%d|%lld %lld %lld|%lld %lld %lld|\n", d0, d1, count, fg1, fg2, fg3, lg1, lg2, lg3);
+}
+
+void diff3(size_t d0, size_t d1, size_t d2) {
+    int64_t pm0, pm1, pm2, pm3;
+    int64_t fg1 = 0, fg2, fg3, fg4, lg1, lg2, lg3, lg4;
+    size_t pos, count = 0;
+
+    if (d0 == 0 || d1 == 0 || d2 == 0) {
+        return;
+    }
+
+    pm2 = PRIMES[0];
+    pm1 = PRIMES[1];
+    pm0 = PRIMES[2];
+    for (pos = 3; pos < PRIME_COUNT; pos++) {
+        pm3 = pm2;
+        pm2 = pm1;
+        pm1 = pm0;
+        pm0 = PRIMES[pos];
+        if (pm0 > 1000000) {
+            break;
+        }
+        if (pm2 - pm3 == d0 && pm1 - pm2 == d1 && pm0 - pm1 == d2) {
+            count++;
+            if (fg1 == 0) {
+                fg1 = pm3;
+                fg2 = pm2;
+                fg3 = pm1;
+                fg4 = pm0;
+            }
+            lg1 = pm3;
+            lg2 = pm2;
+            lg3 = pm1;
+            lg4 = pm0;
+        }
+    }
+
+    printf("%d %d %d|%d|%lld %lld %lld %lld|%lld %lld %lld %lld|\n", d0, d1, d2, count, fg1, fg2, fg3, fg4, lg1, lg2, lg3, lg4);
+}
+
+int main() {
+    initialize();
+
+    printf("differences|count|first group|last group\n");
+
+    diff1(2);
+    diff1(1);
+
+    diff2(2, 2);
+    diff2(2, 4);
+    diff2(4, 2);
+
+    diff3(6, 4, 2);
+
+    return 0;
+}