題意:個球,有紅黃藍綠4種顏色,要求紅球和綠球有偶數個,有多少種排列方式?
思路:
:紅球與綠球都爲偶數的個數
:紅球與綠球恰有一個爲偶數的個數
:紅球與綠球都爲奇數的個數
#include <stdio.h>
#include <vector>
using namespace std;
const int mod = 10007;
typedef vector<int> vec;
typedef vector<vec> mat;
mat mul(mat &A,mat &B)
{
int i,j,k;
mat res( A.size(),vec(B[0].size()) );
for(i = 0; i < A.size(); i++) {
for(j = 0; j < B[0].size(); j++) {
res[i][j] = 0;
for(k = 0; k < A[0].size(); k++) {
res[i][j] = ( res[i][j] + (A[i][k] * B[k][j]) % mod ) % mod;
}
}
}
return res;
}
mat q_pow(mat &A,int b)
{
int i,j;
mat res(A.size(),vec(A[0].size()));
for(i = 0; i < A.size(); i++)
res[i][i] = 1;
while(b) {
if(b & 1) res = mul(res,A);
A = mul(A,A);
b >>= 1;
}
return res;
}
int main(void)
{
int T,n;
mat base(3,vec(3));
scanf("%d",&T);
while(T--) {
base[0][0] = 2,base[0][1] = 1,base[0][2] = 0;
base[1][0] = 2,base[1][1] = 2,base[1][2] = 2;
base[2][0] = 0,base[2][1] = 1,base[2][2] = 2;
scanf("%d",&n);
printf("%d\n",q_pow(base,n)[0][0]);
}
return 0;
}