2017 ACM/ICPC Asia Regional Shenyang Online：number number number hdu 6198【矩阵快速幂】

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #include <vector>
 5 using namespace std;
 6 const int mod = 998244353;
 7 typedef long long LL;
 8 LL n;
 9 typedef vector<LL>vec;
10 typedef vector<vec>mat;
11 mat mul(mat &A, mat &B)
12 {
13     mat C(A.size(), vec(B[0].size()));///分配大小，A的行，B的列
14     for (int i = 0; i<A.size(); i++) ///矩阵A的行
15         for (int k = 0; k<B.size(); k++) ///矩阵B的行
16             for (int j = 0; j<B[0].size(); j++) ///矩阵B的列
17                 C[i][j] = (C[i][j] + A[i][k] * B[k][j] % mod + mod) % mod;
18     return C;
19 }
20 ///计算A^n
21 mat pow(mat A, LL n)
22 {
23     mat B(A.size(), vec(A.size()));///和矩阵A的大小相同
24     for (int i = 0; i<A.size(); i++)
25         B[i][i] = 1;
26     while (n>0)
27     {
28         if (n & 1) B = mul(B, A);
29         A = mul(A, A);
30         n >>= 1;
31     }
32     return B;
33 }
34 void solve()
35 {
36     mat A(2, vec(2));///2*2的矩阵
37     A[0][0] = 1;
38     A[0][1] = 1;
39     A[1][0] = 1;
40     A[1][1] = 0;
41     A = pow(A, n);
42     printf("%d\n", (A[1][0] % mod - 1 + mod) % mod);
43 }
44 int main()
45 {
46     while (~scanf("%lld", &n))
47     {
48         n = 2 * n + 3;
49         solve();
50     }
51 }