uva10870
https://vjudge.net/problem/UVA-10870
裸的矩阵快速幂 注意系数矩阵在前面 因为系数矩阵为d*d 方程矩阵为d * 1 放反了就是d * 1 d * d 不符合矩阵乘法
#include<bits/stdc++.h> using namespace std; typedef long long ll; const int N = 20; struct mat { ll a[N][N]; } x, g; int n, m, d; ll a[N], f[N]; mat operator * (mat a, mat b) { mat ret; memset(ret.a, 0, sizeof(ret.a)); for(int i = 1; i <= d; ++i) for(int j = 1; j <= d; ++j) for(int k = 1; k <= d; ++k) ret.a[i][j] = (ret.a[i][j] + a.a[i][k] % m * b.a[k][j] % m) % m; return ret; } void build() { memset(x.a, 0, sizeof(x.a)); memset(g.a, 0, sizeof(g.a)); for(int i = 1; i <= d; ++i) x.a[i][1] = f[d - i + 1]; for(int i = 1; i <= d; ++i) g.a[1][i] = a[i]; for(int i = 2; i <= d; ++i) g.a[i][i - 1] = 1; } mat power(mat A, int t) { mat ret; memset(ret.a, 0, sizeof(ret.a)); for(int i = 1; i <= d; ++i) ret.a[i][i] = 1; for(; t; t >>= 1, A = A * A) if(t & 1) ret = ret * A; return ret; } int main() { while(scanf("%d%d%d", &d, &n, &m)) { if(n == 0 && d == 0 && m == 0) break; for(int i = 1; i <= d; ++i) scanf("%d", &a[i]), a[i] %= m; for(int i = 1; i <= d; ++i) scanf("%d", &f[i]), f[i] %= m; if(n <= d) { printf("%d\n", f[n]); continue; } build(); mat t = power(g, n - d); t = t * x; printf("%lld\n", t.a[1][1]); } return 0; }