Sequence
Accepts: 59
Submissions: 650
Time Limit: 2000/1000 MS (Java/Others)
Memory Limit: 65536/65536 K (Java/Others)
/* hdu 5667 BestCoder Round #80 矩阵快速幂 F[n] = 1 (n == 1) F[n] = a^b (n == 2) F[n] = a^b * F[n-1]^c *F [n-2] 最开始试了下化简公式,但是无果. 也从矩阵快速幂上面考虑过(毕竟 F[n]与 F[n-1],F[n-2]有关) 但是发现是 乘法运算不知道怎么弄了(2b了) 能够发现运算时基于a的次方的,当a的次方相乘时就变成了他们的次方相加 (好气 TAT) 于是乎 a^g[n] = a^(b + c*g[n-1] * g[n-2]) 然后用类似快速幂求斐波那契数的方法即可 F[n] F[n-1] 1 C 1 0 F[n-1] F[n-2] 1 * 1 0 0 b 0 1 hhh-2016-04-18 20:36:40 */ #include <iostream> #include <cstdio> #include <cstring> #include <vector> #include <map> #include <algorithm> #include <functional> #include <math.h> using namespace std; #define lson (i<<1) #define rson ((i<<1)|1) typedef long long ll; const int maxn = 100040; struct Matrix { ll ma[3][3]; Matrix() { memset(ma,0,sizeof(ma)); } }; Matrix mult(Matrix ta,Matrix tb, ll mod) { Matrix tc; for(int i = 0; i < 3; i++) { for(int j = 0; j < 3; j++) { tc.ma[i][j] = 0; for(int k = 0; k < 3; k++){ tc.ma[i][j] += (ta.ma[i][k] * tb.ma[k][j])%mod; tc.ma[i][j] %= mod; } } } return tc; } Matrix Mat_pow(Matrix ta,ll n,ll mod) { Matrix t; for(int i = 0; i < 3; i++) t.ma[i][i] = 1; while(n) { if(n & 1) t = mult(t,ta,mod); ta = mult(ta,ta,mod); n >>= 1; } return t; } ll pow_mod(ll a,ll n,ll mod) { ll t = 1; a %= mod ; while(n) { if(n & 1) t = t*a%mod; a = a*a%mod; n >>= 1; } return t; } Matrix mat; Matrix an; ll a,b,c; void ini(ll mod) { mat.ma[0][0] = c,mat.ma[0][1] = 1,mat.ma[0][2] = 0; mat.ma[1][0] = 1,mat.ma[1][1] = 0,mat.ma[1][2] = 0; mat.ma[2][0] = b,mat.ma[2][1] = 0,mat.ma[2][2] = 1; an.ma[0][0] = (b+b*c%mod)%mod,an.ma[0][1] = b,an.ma[0][2] = 1; an.ma[1][0] = b,an.ma[1][1] = 0,an.ma[2][1] = 1; } ll mod,n; int main() { int T; scanf("%d",&T); while(T--) { scanf("%I64d%I64d%I64d%I64d%I64d",&n,&a,&b,&c,&mod); a%=mod,b%=mod,c%=mod; ini(mod-1); if(n == 1) { printf("1 "); } else if(n == 2) printf("%I64d ",pow_mod(a,b,mod)); else { mat = Mat_pow(mat,n-3,mod-1); mat = mult(an,mat,mod-1); ll ci = mat.ma[0][0]; //cout << ci <<endl; printf("%I64d ",pow_mod(a,ci,mod)); } } return 0; }