35 lines
695 B
C++
35 lines
695 B
C++
/** The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.
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Find the sum of all the primes below two million. */
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#include "0.hpp"
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#include <sys/timeb.h>
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uu factor(uu a, uu min = 1)
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{
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uu temp = min;
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uu sqr = (int)(sqrt((double)a) + _eps);
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while(temp < sqr) if(a % ++temp == 0) break;
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if(a % temp == 0) return temp;
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else return 1;
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}
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int main()
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{
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const uu _max = 2000000;
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uu sum = 0;
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timeb start, end;
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ftime(&start);
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for(uu i = 3; i <= _max; i += 2) {
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if(factor(i) == 1) {
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//cout << i << "\t";
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sum += i;
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}
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}
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sum += 2;
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ftime(&end);
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cout << sum << endl;
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cout << (end.time - start.time) * 1000 + end.millitm - start.millitm << endl;
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return 0;
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}
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