47 lines
891 B
C
47 lines
891 B
C
#include <stdio.h>
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#include <stdlib.h>
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int main(void) {
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FILE *file1 = fopen("input.bin", "rb");
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if (!file1) {
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perror("Error opening input.bin");
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return 1;
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}
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int n;
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if (fread(&n, sizeof(n), 1, file1) != 1) {
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perror("Error reading input.bin");
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fclose(file1);
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return 1;
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}
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fclose(file1);
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printf("Got: %d\n", n);
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// Primes or smth
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int count = 0;
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for (int i = 2; i < 500000; i++) {
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int prime = 1;
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for (int d = 2; d * d <= n; d++) {
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if (n % d == 0) {
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prime = 0;
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break;
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}
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}
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count += prime;
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n += 2;
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}
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FILE *file2 = fopen("output.bin", "wb");
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if (!file2) {
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perror("Error opening output.bin");
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return 1;
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}
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fwrite(&count, sizeof(count), 1, file2);
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fclose(file2);
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return 0;
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}
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