自己是在是弱,看了半天才看懂题解
写公式实在是麻烦,搬家一份:
#include<iostream> #include<cstdio> #include<cstring> #include<cstdlib> #define N 101000 #define pos(i,a,b) for(int i=(a);i<=(b);i++) using namespace std; #define LL long long int t,n,m; int notprime[N],prime[N],mu[N]; LL f[N]; void get_mu(){ notprime[1]=1;mu[1]=1; pos(i,2,N-10){ if(!notprime[i]){ prime[++prime[0]]=i; mu[i]=-1; } for(int j=1;j<=prime[0]&&prime[j]*i<=N-10;j++){ notprime[prime[j]*i]=1; if(i%prime[j]==0){ mu[i*prime[j]]=0; break; } mu[i*prime[j]]=-mu[i]; } } pos(i,1,N-10) mu[i]+=mu[i-1]; pos(i,1,N-10){ int last(0); for(int j=1;j<=i;j=last+1){ last=i/(i/j); f[i]+=(i/j)*1ll*(last-(j-1)); } } } LL get_ans(){ int last(0); LL res(0); for(int i=1;i<=n;i=last+1){ last=min(n/(n/i),m/(m/i)); res+=f[n/i]*f[m/i]*(mu[last]-mu[i-1]); } return res; } int main(){ scanf("%d",&t); get_mu(); while(t--){ scanf("%d%d",&n,&m);if(n>m) swap(n,m); printf("%lld\n",get_ans()); } return 0; }
时间: 2024-10-13 12:03:33