38 lines
985 B
C
38 lines
985 B
C
#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <stdbool.h>
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#include "primes.h"
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int main () {
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long size = 10000;
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long* primes;
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bool* primesTable;
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long numPrimes = listOfPrimes (size, &primes, &primesTable);
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long n = 37;
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while (n < size) {
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if (!primesTable[n]) {
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long p = 0;
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bool decomposable = false;
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while (n > primes[p]) {
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long sq = (n - primes[p]) / 2;
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long sqrtr = sqrt (sq);
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if (sqrtr * sqrtr == sq) {
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// printf ("%lli = %lli + 2 x %lli²\n", n, primes[p], sqrtr);
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decomposable = true;
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n += 2;
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break;
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}
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else
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p++;
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}
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if (!decomposable) {
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printf ("%lli cannot be written as such.\n", n);
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break;
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}
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}
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else
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n += 2;
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}
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}
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