HDU-2017 ACM/ICPC Asia Regional Shenyang Online-1005-number number number

ACM模版

描述

题解

矩阵乘法，简单裸题。

代码

#include <iostream>#include <cstring>using namespace std;typedef long long ll;const int MOD =  998244353;ll k;ll A[2][2];ll res[2][2];ll c[2][2];void mull(ll a[2][2], ll b[2][2]){    memset(c, 0, sizeof(c));    for (int i = 0; i < 2; i++)    {        for (int j = 0; j < 2; j++)        {            for (int k = 0; k < 2; k++)            {                c[i][j] = (c[i][j] + a[i][k] * b[k][j] % MOD) % MOD;            }        }    }    memcpy(a, c, sizeof(c));}void mul_pow(ll n){    res[0][0] = res[1][1] = 1;    res[1][0] = res[0][1] = 0;    while (n)    {        if (n & 1)        {            mull(res, A);        }        mull(A, A);        n >>= 1;    }}int main(){    while (~scanf("%lld", &k))    {        k = (k - 1) * 2 + 4;        A[0][0] = 1, A[0][1] = 1;        A[1][0] = 1, A[1][1] = 0;        mul_pow(k);        printf("%lld\n", (res[0][0] - 1 + MOD) % MOD);    }    return 0;}