HDU 5015 233 Matrix（矩阵快速幂）

题目地址：http://acm.hdu.edu.cn/showproblem.php?pid=5015

AC代码：

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <stack>
#include <map>
#include <cstring>
#include <climits>
#include <cmath>
#include <cctype>
const int inf = 0x3f3f3f3f;//1061109567
typedef long long LL;
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
const int mod = 10000007;
using namespace std;
int n;
struct node
{
    LL a[15][15];
};
node matrixmul(node a,node b)
{
    node c;
    for(int i=0; i<=n+1; i++)
    {
        for(int j=0; j<=n+1; j++)
        {
            c.a[i][j] = 0;
            for(int k=0; k<=n+1; k++)
            {
                c.a[i][j] += a.a[i][k] * b.a[k][j];//怕中间结果超int，用long long
                c.a[i][j] %= mod;
            }
        }
    }
    return c;
}
node quickmod(node s,int k)
{
    node ans;
    memset(ans.a,0,sizeof(ans.a));
    for(int i=0; i<=n+1; i++)
        ans.a[i][i] = 1;
    while(k)
    {
        if(k & 1)
        {
            ans = matrixmul(ans,s);
        }
        k = k >> 1;
        s = matrixmul(s,s);
    }
    return ans;
}
int main()
{
    int m;
    while(scanf("%d%d",&n,&m) != EOF)
    {
        node sa,sb;
        memset(sa.a,0,sizeof(sa.a));
        sa.a[0][0] = 23;
        for(int i=1; i<=n; i++)
        {
            scanf("%I64d",&sa.a[i][0]);
        }
        sa.a[n+1][0] = 3;
        memset(sb.a,0,sizeof(sb.a));
        for(int i=0; i<n+1; i++)
            sb.a[i][0] = 10;
        for(int i=0; i<=n+1; i++)
            sb.a[i][n+1] = 1;
        for(int i=1; i<=n; i++)
        {
            for(int j=1; j<=i; j++)
            {
                sb.a[i][j] = 1;
            }
        }
        sb = quickmod(sb,m);
        sb = matrixmul(sb,sa);
        printf("%I64d\n",sb.a[n][0]);
    }
    return 0;
}