Euler function templates

Two ways to find the Euler function value of a single number:

1#include <iostream>2 using namespacestd;3 4 intPhiintN)5 {6     intAns =N;7      for(inti =2; I * I <= N; i++ )8     {9         if(n% i = =0 )Ten         { OneAns-= ans/i; A              Do -             { -n = n/i; the} while(n% i = =0 ); -         } -     } -     if(n! =1 ) +     { -Ans-= ans/N; +     } A     returnans; at } -  - intPphi (intN) - { -     intAns =1; -      for(inti =2; I * I <= N; i++ ) in     { -         if(n% i = =0 ) to         { +Ans *= I-1; -n = n/i; the              while(n% i = =0 ) *             { $Ans *=i;Panax Notoginsengn = n/i; -             } the         } +     } A     if(n! =1 ) the     { +Ans *= N-1; -     } $     returnans; $ } -  - intMain () the { -     intT;WuyiCIN >>T; the      while(t-- ) -     { Wu         intN; -CIN >>N; Aboutcout << pphi (n) <<Endl; $     } -     return 0; -}

The Sieve method to find Euler function:

1#include <iostream>2 using namespacestd;3 4 Const intN =32768;5 intPhi[n];6 7 voidInit ()8 {9phi[0] = phi[1] =1;Ten      for(inti =2; i < N; i++ ) One     { APhi[i] =i; -     } -      for(inti =2; i < N; i++ ) the     { -         if(Phi[i] = =i) -         { -phi[i]--; +              for(intj = i + i; J < N; J + =i) -             { +PHI[J]-= phi[j]/i; A             } at         } -     } - } -  - intMain () - { in init (); -     intT; toCIN >>T; +      while(t-- ) -     { the         intN; *CIN >>N; $cout << Phi[n] <<Endl;Panax Notoginseng     } -     return 0; the}

Template title: Hdu 1286 POJ 1284

Euler function templates