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hdu 2814 Interesting Fibonacci

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题目大意:就是给你两个函数,一个是F(n) = F(n-1) + F(n-2),
F(0) = 0, F(1) = 1;
还有一个是 G(n) = G(n-1)^F(a^b);
G(1) = F(a^b);
求G(n) % c;
范围:A, B, N, C (10<=A, B<2^64, 2<=N<2^64, 1<=C<=300)

注意了:c的范围是1<= C <= 300,所以说它一定会有循环 节:
解题思路: 首先算G(1) = F(a^b),设a^b的循环节是len;
F(a^b)%c = F(a^b%len)%c;
一边加一边取余

然后算G(n)%c = F(a^b)^(F(a^b)^(n-1)) % c;
G(n)%c = F(a^b)^(F(a^b)^(n-1)%phi(c)+phi(c))%c;
F(a^b)^(n-1)%phi(c)+phi(c) == (F(a^b)%phi(c)^(n-1))+phi(c)
F(a^b)%phi(c) 有循环节。同上,详细详见代码

上代码:

/*
2015 - 8 - 16 下午
Author: ITAK

今日的我要超越昨日的我,明日的我要胜过今日的我,
以创作出更好的代码为目标,不断地超越自己。

*/ #include <iostream> #include <cstdio> using namespace std; //高速幂取余 int quick_mod(int a, unsigned long long b, int c) { int ans = 1; a %= c; while(b) { if(b & 1) ans = (ans*a) % c; b >>= 1; a = (a*a) % c; } return ans; } //欧拉函数 int Phi(int m) { int ans = m; for(int i=2; i*i<=m; i++) { if(m%i == 0) ans -= ans/i; while(m%i == 0) m /= i; } if(m > 1) ans -= ans/m; return ans; } //公式:x^y % c == x^(y%phi(c)+phi(c))%c; int data[90005],data1[90005]; int main() { //注意不要用long long,用unsigned long long unsigned long long a, b, n; int c, c1, t, n1, n2, tmp; int g[10], len=0, len_c=0, len_e=0; scanf("%d",&t); for(int k=1; k<=t; k++) { //cin>>a>>b>>n>>c; scanf("%lld%lld%lld%d",&a,&b,&n,&c); if(c == 1) { printf("Case %d: 0\n",k); continue; } data[0]=0, data[1]=1; data1[0]=0, data1[1]=1; for(int i=2; i<90005; i++) { data[i] = (data[i-1]+data[i-2])%c; if(data[i]==1 && data[i-1]==0) { len = i-1;//c的循环节 break; } } c1 = Phi(c); if(c1 > 1) { for(int i=2; i<90005; i++) { data1[i] = (data1[i-1]+data1[i-2])%c1;

hdu 2814 Interesting Fibonacci