P1939【模板】矩阵加速（数列）

P1939【模板】矩阵加速（数列）
难受就难受在a[i-3],这样的话让k=3就好了。

 #include<iostream>
 #include<cstdio>
 #include<queue>
 #include<algorithm>
 #include<cmath>
 #include<ctime>
 #include<set>
 #include<cstring>
 #define mod 1000000007
 #define For(i,a,b) for(register long long i=a;i<=b;i++)
 #define p(a) putchar(a)
 #define g() getchar()
 //by war
 //2017.10.26
 using namespace std;
 long long k,t;

 struct matrix
 {
     long long a[];
     long long b[][];
     matrix operator *(const matrix&c)const
     {
         matrix r;
         For(i,,)
           For(j,,)
           {
              r.b[i][j]=;
              For(k,,)
             r.b[i][j]=(r.b[i][j]+(b[i][k]*c.b[k][j])%mod)%mod;
           }
         return r;
     }
 }a;

 void in(long long &x)
 {
     long long y=;
     char c=g();x=;
     while(c<''||c>'')
     {
     if(c=='-')
     y=-;
     c=g();
     }
     while(c<=''&&c>='')x=x*+c-'',c=g();
     x*=y;
 }
 void o(long long x)
 {
     if(x<)
     {
         p('-');
         x=-x;
     }
     if(x>)o(x/);
     p(x%+'');
 }

 matrix ksm(matrix a,long long b)
 {
     matrix r=a;b--;
     if(b==)
     return r;
     while(b%==)
     {
         a=a*a;
         b>>=;
     }
     while(b>)
     {
         if(b%==)
         r=r*a;
         a=a*a;
         b>>=;
     }
     return r;
 }

 int main()
 {
     in(t);
     while(t--)
     {
     in(k);
     if(k==||k==||k==)
     {
         o(),p('\n');

     }
     else
     {
     a.a[]=;
     a.a[]=;
     a.a[]=;
     a.b[][]=;
     a.b[][]=;
     a.b[][]=;
     a.b[][]=;
     a.b[][]=;
     a.b[][]=;
     a.b[][]=;
     a.b[][]=;
     a.b[][]=;
     matrix r,ans;
     r=ksm(a,k-);
     for(register int i=;i<=;i++)
           For(j,,)
           {
              ans.a[i]=;
              For(k,,)
             ans.a[i]=(ans.a[i]+(a.a[i]*r.b[k][j])%mod)%mod;
           }
     For(i,,)
     o((ans.a[i]%mod+mod)%mod),p('\n');
     }

     }
      return ;
 }