HDU 1588 Gauss Fibonacci Matrix

First, the FIB series can be introduced to the matrix solution at will, and then here is to deal with a problem about the sum of the matrix proportional series. Here is a solution of logn, similar

A ^ 0 + A ^ 1 + a ^ 2 + A ^ 3 = a ^ 0 + A ^ 1 + a ^ 2 * (a ^ 0 + A ^ 1) just deal with it.

#include <cstdio>#include <cstring>#include <algorithm>#include <queue>#include <stack>#include <map>#include <set>#include <climits>#include <iostream>#include <string>using namespace std; #define MP make_pair#define PB push_backtypedef long long LL;typedef unsigned long long ULL;typedef vector<int> VI;typedef pair<int, int> PII;typedef pair<double, double> PDD;const int INF = INT_MAX / 3;const double eps = 1e-8;const LL LINF = 1e17;const double DINF = 1e60;const int maxn = 6;LL k, b, n, mod;struct Matrix {    int n, m;    LL data[maxn][maxn];    Matrix(int n = 0, int m = 0): n(n), m(m) {        memset(data, 0, sizeof(data));    }};Matrix operator * (Matrix a, Matrix b) {    int n = a.n, m = b.m;    Matrix ret(n, m);    for(int i = 1; i <= n; i++) {        for(int j = 1; j <= m; j++) {            for(int k = 1; k <= a.m; k++) {                ret.data[i][j] += a.data[i][k] * b.data[k][j];                ret.data[i][j] %= mod;            }        }    }    return ret;}Matrix operator + (Matrix a, Matrix b) {    for(int i = 1; i <= a.n; i++) {        for(int j = 1; j <= a.m; j++) {            a.data[i][j] += b.data[i][j];            a.data[i][j] %= mod;        }    }    return a;}Matrix pow(Matrix mat, LL k) {    if(k == 0) {        Matrix ret(mat.n, mat.m);        for(int i = 1; i <= mat.n; i++) ret.data[i][i] = i;        return ret;    }    if(k == 1) return mat;    Matrix ret = pow(mat * mat, k / 2);    if(k & 1) ret = ret * mat;    return ret;}Matrix calc(Matrix mat, LL p) {    if(p == 0) return pow(mat, b);    if(p == 1) return pow(mat, b) + pow(mat, k + b);    int midval = (p + 1) % 2 == 0 ? (p / 2) : (p / 2) - 1;    Matrix ret = calc(mat, midval);    ret = ret + pow(mat, (midval + 1) * k) * ret;    if((p + 1) & 1) ret = ret + pow(mat, p * k + b);    return ret;}int main() {    while(cin >> k >> b >> n >> mod) {        Matrix A(2, 2);        A.data[1][1] = A.data[1][2] = A.data[2][1] = 1;        A.data[2][2] = 0;        Matrix ans = calc(A, n - 1);        cout << ans.data[2][1] << endl;    }    return 0;}

　　

HDU 1588 Gauss Fibonacci Matrix