HDU 5407
題意 : 給你一個 N 求 C(N,1 to N ) 的LCM;
有定理: (不會推)
g (n ) = C(N,1 to N ) 的LCM,???
f? (n? )?? = Lcm ( 1, to? n)
g ( n ) = f(n + 1 ) / ( n + 1 );
f ( n ) =? f (n –1 ) * p? (( if? n 為 質數 p 的k 次方數)
???????? or? = f (n – 1 );
根據上式就可以很快得出 g (n )了;
#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> using namespace std; typedef long long ll; const int maxn = 1e6 +131; const ll mod = 1e9 + 7; int Prime[maxn]; bool Jug[maxn]; int Cnt; void Make() {Cnt = 0;for(int i = 2; i < maxn; ++i){if(Jug[i] == false){Prime[Cnt++] = i;for(int j = i; j < maxn; j += i)Jug[j] = true;}} }ll Fun[maxn]; void MK() {Fun[1] = 1;for(int i = 2; i < maxn; ++i){int tmp = i;bool jj = true;for(int j = 0; j <Cnt && Prime[j] <= tmp; ++j){if(tmp % Prime[j] == 0){while(tmp % Prime[j] == 0) tmp /= Prime[j];if(tmp > 1) jj = false;break;}}if(jj) Fun[i] = Fun[i-1] * i % mod;else Fun[i] = Fun[i-1];} }ll ppow(ll a, ll b) {ll ret = 1;while(b){if(b & 1) ret = ret * a % mod;a = a * a % mod;b >>= 1;}return ret; }int main() {Make();//MK();int t;scanf("%d",&t);while(t--){int n;scanf("%d",&n);ll ans = 1;for(int i = 0; i < Cnt && Prime[i] <= n; ++i){ll tmp = Prime[i];while(tmp <= n){if((n+1) % tmp != 0)ans = ans * Prime[i] % mod;tmp = tmp * Prime[i];}}printf("%lld\n",ans);}return 0; }轉載于:https://www.cnblogs.com/aoxuets/p/4746278.html
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