Style changes to primes
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20
primes.c
20
primes.c
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@ -8,7 +8,7 @@
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* runs in O(sqrt(n))
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*
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*/
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bool isPrime (long n) {
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bool isPrime(long n) {
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if (n == 0 || n == 1)
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return false;
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@ -26,7 +26,7 @@ bool isPrime (long n) {
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* runs in O(sqrt(n)/ln(n))
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*
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*/
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bool isPrimeMem (long n, long* primes) {
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bool isPrimeMem(long n, long* primes) {
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if (n == 0 || n == 1)
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return false;
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if (n == 2 || n == 3)
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@ -50,15 +50,15 @@ bool isPrimeMem (long n, long* primes) {
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* where the 0-based ith element is true if i is prime
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* returns: number of primes in *primes_ptr
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*
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* N.B. numOfPrimesUpper is an upper-bound of
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* the prime-counting function, given by
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* N.B. numOfPrimesUpper is an upper-bound of
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* the prime-counting function, given by
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* n/ln(n) * 1.25506
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*
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* runs in O(n * sqrt(n)/ln(n)) (not a tight bound)
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*
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*/
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long listOfPrimes (long n, long** primes_ptr, bool** primesTable_ptr) {
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long listOfPrimes(long n, long** primes_ptr, bool** primesTable_ptr) {
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*primesTable_ptr = calloc (n + 1, sizeof (bool));
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if (n == 0 || n == 1) {
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@ -66,23 +66,23 @@ long listOfPrimes (long n, long** primes_ptr, bool** primesTable_ptr) {
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return 0;
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}
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long numOfPrimesUpper = (long) (n/log(n) * 1.25506);
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long numOfPrimesUpper = (long) (n/log(n) * 1.25506);
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*primes_ptr = malloc (sizeof (long) * numOfPrimesUpper);
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long numOfPrimes = 0;
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for (long i = 0; i <= n; i++) {
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if (isPrimeMem (i, *primes_ptr)) {
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if (isPrimeMem(i, *primes_ptr)) {
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(*primes_ptr)[numOfPrimes] = i;
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(*primesTable_ptr)[i] = true;
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numOfPrimes++;
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}
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}
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if (numOfPrimes < numOfPrimesUpper) {
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long* tmp = realloc (*primes_ptr,
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long* tmp = realloc (*primes_ptr,
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sizeof (long) * numOfPrimes);
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if (tmp != NULL)
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*primes_ptr = tmp;
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}
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return numOfPrimes;
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}
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@ -92,7 +92,7 @@ long listOfPrimes (long n, long** primes_ptr, bool** primesTable_ptr) {
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* runs in O(n ln(ln(n))) apparently
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*
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*/
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void sieveOfEratosthenes (int n, bool** primesTable_ptr) {
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void sieveOfEratosthenes(int n, bool** primesTable_ptr) {
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*primesTable_ptr = malloc (sizeof (bool) * (n + 1));
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for (int i = 0; i <= n; i++)
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(*primesTable_ptr)[i] = true;
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10
primes.h
10
primes.h
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@ -1,4 +1,6 @@
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bool isPrime (long n);
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bool isPrimeMem (long n, long* primes);
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long listOfPrimes (long n, long** primes_ptr, bool** primesTable_ptr);
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void sieveOfEratosthenes (int n, bool** primesTable_ptr);
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#include <stdbool.h>
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bool isPrime(long n);
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bool isPrimeMem(long n, long* primes);
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long listOfPrimes(long n, long** primes_ptr, bool** primesTable_ptr);
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void sieveOfEratosthenes(int n, bool** primesTable_ptr);
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