math/totient.cpp

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• Last update: 2020-10-24 12:57:36+09:00

Required by

• mod/tetration.cpp

Verified with

• test/aoj/NTL_1_D.test.cpp
• test/yosupo/tetration_mod.test.cpp
• test/yukicoder/0472.test.cpp

Code

#ifndef call_from_test
#include <bits/stdc++.h>
using namespace std;
#endif
//BEGIN CUT HERE
template<typename T>
T totient(T n){
  T res=n;
  for(T i=2;i*i<=n;i++){
    if(n%i) continue;
    res=res/i*(i-1);
    while(n%i==0) n/=i;
  }
  if(n!=1) res=res/n*(n-1);
  return res;
}
//END CUT HERE
#ifndef call_from_test
signed main(){
  return 0;
}
#endif

#line 1 "math/totient.cpp"

#include <bits/stdc++.h>
using namespace std;
#endif
//BEGIN CUT HERE
template<typename T>
T totient(T n){
  T res=n;
  for(T i=2;i*i<=n;i++){
    if(n%i) continue;
    res=res/i*(i-1);
    while(n%i==0) n/=i;
  }
  if(n!=1) res=res/n*(n-1);
  return res;
}
//END CUT HERE
#ifndef call_from_test
signed main(){
  return 0;
}
#endif

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