矩阵快速幂

#include<cstdio>#include<iostream>#include<cmath>#include<vector>#include<cstring>#include<set>#include<algorithm>#include<map>using namespace std;typedef long long LL;typedef  vector<int> vec;typedef  vector<vec> mat;mat mul(mat A, mat B) { //两个矩阵的相乘 B*A后生成，A的列为C的列，B的行为C的行    mat C(A.size(), vec(B[0].size()));    for (int i=0; i<A.size(); i++) {        for (int j=0; j<B.size(); j++) {            for (int k=0; k<B[0].size(); k++)                C[i][k]+=B[i][j]*A[j][k];        }    }    return C;}mat pow(mat A, int n) {  //快速幂    mat B(A.size(), vec(A.size()));    for (int i=0; i<A.size(); i++)  //单位矩阵        B[i][i] = 1;    while (n) {        if (n&1)            B = mul(B, A);        A = mul(A, A);        n >>= 1;    }    return B;}int main() {    int n;    cin>>n;    mat A(2, vec(2));    A[0][0] = 1, A[0][1] = 1;    A[1][0] = 1, A[1][1] = 0;    A = pow(A, n);    printf("%d\n", A[1][0]);    return 0;}