67 lines
1.0 KiB
C++
67 lines
1.0 KiB
C++
/*
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* YOUR INFO HERE!
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*/
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// FINAL VERSION:
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unsigned long long largest_prime_factor(unsigned long long n){
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unsigned long long lpf, p, s, t;
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lpf = 1;
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p = 2;
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s = 1;
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t = n / p;
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while (p <= t){
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if (n % p == 0){
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lpf = p;
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n /= p;
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while (n % p == 0){
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n /= p;
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}
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}
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p += s;
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s = 2;
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t = n / p;
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}
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if (n > lpf){
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lpf = n;
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}
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return lpf;
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}
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#ifdef EULER_PROBLEM
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// BUILDING AREA:
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struct Euler_In{
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unsigned long long n;
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};
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struct Euler_Result{
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unsigned long long lpf;
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};
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static const unsigned long long NUMBER = 600851475143;
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Euler_Result euler_main(Euler_In in){
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Euler_Result result;
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result.lpf = largest_prime_factor(NUMBER);
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return result;
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}
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void euler_print(Euler_Result answer, Euler_In in){
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printf("%llu\n", answer.lpf);
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}
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#if 0
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#define EULER_CHECK
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bool euler_check(Euler_Result answer, Euler_In in){
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bool result = 1;
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return result;
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}
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#endif
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#endif
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