[SDOI2017]数字表格
SOL:
怎么说呢,套路题。随便数论分块就好了
// luogu-judger-enable-o2 #include<bits/stdc++.h> #define N 1000007 #define LL long long #define pri p #define mo 1000000007 using namespace std; int pri[N/10],tot,u[N],usd[N]; LL f[N],ff[N],ax,g[N]; inline LL qsm(LL x,LL y=mo-2) { static LL anw; for (anw=1,x=x%mo;y;y>>=1,x=x*x%mo) if (y&1) anw=anw*x%mo; return anw; } void pre(){ for (int i=2;i<N;i++) { if (!usd[i]) pri[++tot]=i,u[i]=-1; for (int j=1;j<=tot&&i*pri[j]<N;j++) { if (i%p[j]==0) { u[i*p[j]]=0; usd[i*p[j]]=1; break;} u[i*p[j]]=-u[i]; usd[i*p[j]]=1; } } ff[0]=ff[1]=f[1]=1; u[1]=1; g[1]=1; for (int i=2;i<N;i++) f[i]=f[i-1]+f[i-2],f[i]%=mo,g[i]=qsm(f[i]),ff[i]=1; for (int i=1;i<N;i++) { if (!u[i]) continue; for (int j=i;j<N;j+=i) ff[j]=ff[j]*(u[i]==1?f[j/i]:g[j/i])%mo; } for (int i=2;i<N;i++) ff[i]=ff[i-1]*ff[i]%mo; } int n,m,T; LL ni,ans; signed main () { // freopen("a.in","r",stdin); pre(); scanf("%d",&T); while (T--) { scanf("%d%d",&n,&m); if (n>m) swap(n,m); ans=1; for (int i=1,last;i<=n;i=last+1) { last=min(n/(n/i),m/(m/i)); ni=qsm(ff[i-1]); ans=ans*qsm(ff[last]*ni,1ll*(n/i)*(m/i))%mo; } printf("%lld\n",ans); } return 0; }