矩阵快速幂-斐波那契
陈子骏
2018-07-17 07:24:45
```
#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;
const int mod = 10000;
const int maxn = 35;
int N;
struct Matrix {
int mat[maxn][maxn];
int x, y;
Matrix() {
memset(mat, 0, sizeof(mat));
for (int i = 1; i <= maxn - 5; i++) mat[i][i] = 1;
}
};
inline void mat_mul(Matrix a, Matrix b, Matrix &c) {
memset(c.mat, 0, sizeof(c.mat));
c.x = a.x; c.y = b.y;
for (int i = 1; i <= c.x; i++) {
for (int j = 1; j <= c.y; j++) {
for (int k = 1; k <= a.y; k++) {
c.mat[i][j] += (a.mat[i][k] * b.mat[k][j]) % mod;
c.mat[i][j] %= mod;
}
}
}
return ;
}
inline void mat_pow(Matrix &a, int z) {
Matrix ans, base = a;
ans.x = a.x; ans.y = a.y;
while (z) {
if (z & 1 == 1) mat_mul(ans, base, ans);
mat_mul(base, base, base);
z >>= 1;
}
a = ans;
}
int main() {
while (cin >> N) {
switch (N) {
case -1: return 0;
case 0: cout << "0" << endl; continue;
case 1: cout << "1" << endl; continue;
case 2: cout << "1" << endl; continue;
}
Matrix A, B;
A.x = 2; A.y = 2;
A.mat[1][1] = 1; A.mat[1][2] = 1;
A.mat[2][1] = 1; A.mat[2][2] = 0;
B.x = 2; B.y = 1;
B.mat[1][1] = 1; B.mat[2][1] = 1;
mat_pow(A, N - 1);
mat_mul(A, B, B);
cout << B.mat[1][1] << endl;
}
return 0;
}
```