开发笔记:GCD（欧拉函数）

1 #include
2 using namespace std;
3 #define lson l,mid,rt<<1
4 #define rson mid+1,r,rt<<1|1
5 #define IT set::iterator
6 #define pb push_back
7 #define eb emplace_back
8 #define maxn 200005
9 #define eps 1e-6
10 #define PI acos(-1.0)
11 #define rep(k,i,j) for(int k=i;k12 typedef long long ll;
13 typedef pair<int,int> pii;
14 typedef pairpll;
15 typedef pairint> pli;
16 typedef pairint,string>,pii> ppp;
17 typedef unsigned long long ull;
18 const long long MOD=1000000007;
19 const double oula=0.57721566490153286060651209;
20 const int INF=0x3f3f3f3f;
21 using namespace std;
22
23
24 ll Euler(ll n){
25 ll ans=n;
26 for(ll i=2;i*i<=n;i++){
27 if(n%i==0) ans=ans/i*(i-1);
28 while(n%i==0) n/=i;
29 }
30 if(n>1) ans=ans/n*(n-1);
31 return ans;
32 }
33
34 int main(){
35 std::ios::sync_with_stdio(false);
36 int t;
37 cin>>t;
38 while(t--){
39 ll n,m;
40 cin>>n>>m;
41 ll ans=0;
42 for(int i=1;i*i<=n;i++){
43 if(n%i==0){
44 if(i>=m) ans+=Euler(n/i);
45 if(i*i!=n&&n/i>=m) ans+=Euler(i);
46 }
47 }
48 cout<endl;
49 }
50 }