【数论】 HDOJ 5407 CRB and Candies

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数论结论题。。。就是1-n+1的lcm除以n+1。。。。不知道结论怎么做？----没法做。。。

#include <bits/stdc++.h>using namespace std;typedef long long LL;const int maxn = 1000005;const int N = 1000000;const int mod = 1e9+7;int val[maxn];LL f[maxn];LL g[maxn];int p[maxn];LL powmod(LL a, LL b){LL res = 1, base = a;while(b) {if(b % 2) res = res * base % mod;base = base * base % mod;b /= 2;}return res;}void init(){for(int i = 2; i < maxn; i++) if(p[i] == 0)for(int j = i + i; j < maxn; j += i) p[j] = 1;for(int i = 2; i < maxn; i++) if(p[i] == 0)for(LL j = (LL)i; j < maxn; j *= i)val[j] = i;f[1] = 1;for(int i = 2; i < maxn; i++) if(val[i]) f[i] = f[i-1] * val[i] % mod;else f[i] = f[i-1];for(int i = 1; i <= N; i++) g[i] = f[i+1] * powmod(i+1, mod-2) % mod;}int main(){init();int _;scanf("%d", &_);while(_--) {int x;scanf("%d", &x);printf("%lld\n", g[x]);}return 0;}

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