43 lines
805 B
C
43 lines
805 B
C
#include <stdio.h>
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#include <math.h>
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int gcd(int a, int b);
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int main(int argc, char *argv[])
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{
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int lim = 1500000;
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int i, n, m, p, c, odd;
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char sieve[lim + 1];
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for(i = 0; i <= lim; ++i){
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sieve[i] = 0;
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}
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odd = c = 0;
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for(n = 2; n <= (sqrt(2*lim + 1) - 1)/ 2; ++n){
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for(m = odd + 1; m < n && m <= (lim / 2*n) - n; m += 2){
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if(gcd(n, m) == 1){
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p = 2*n * (n + m);
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for(i = p; i <= lim; i += p){
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sieve[i] += 1;
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}
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}
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}
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odd = !odd;
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}
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for(i = 0; i <= lim; i += 2){
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if(sieve[i] == 1){
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++c;
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}
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}
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printf("%d\n", c);
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}
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int gcd(int a, int b)
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{
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int c;
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while (a != 0){
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c = a; a = b%a; b = c;
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}
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return b;
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}
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