37 lines
676 B
C
37 lines
676 B
C
#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#define YES 1
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#define NO 0
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int main(int argc, char *argv[]) {
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int limit=2000000;
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int i,m;
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int crosslimit=sqrt(2000000);
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char *sieve=(char *)malloc(sizeof(char)*limit);
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double sum;
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for (i=0;i<limit;i++)
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sieve[i]=NO;
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for (i=4;i<limit;i+=2) {
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sieve[i]=1;
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}
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for (i=3; i<crosslimit; i+=2) {
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if (!sieve[i]) {
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for ( m=i*i ; m<limit; m+=2*i ) {
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sieve[m]=YES;
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}
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}
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}
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sum=0;
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for (i=2;i<limit;i++) {
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if (!sieve[i]) {
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sum += i;
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}
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}
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printf("%lf\n",sum);
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}
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