HDU 3802 Ipad,IPhone

http://wutyyzchangde.blog.163.com/blog/static/172226566201132311311374/

#include <cstdio>
typedef struct{
 __int64 matrix[2][2];
}Matrix;
__int64 powermod(__int64 x,__int64 n,__int64 p){
    __int64 res = 1;
    for(;n;n>>=1){
        if(n&1)
        res=(res*x)%p;
        x=(x*x)%p;
    }
    return res;
}
Matrix multi(Matrix x,Matrix y,__int64 p){
    Matrix res;
    int i,j,k;
    __int64 sum;
    for(i=0;i<2;i++)
    for(j=0;j<2;j++){
        sum=0;
        for(k=0;k<2;k++)sum+=(x.matrix[i][k]*y.matrix[k][j])%p;
        res.matrix[i][j] = sum%p;
    }
    return res;
}
Matrix Mat_powermod(Matrix x,__int64 n,__int64 p){
    Matrix res;
    int i,j;
    for(i=0;i<2;i++)
    for(j=0;j<2;j++){
        if(i==j)
        res.matrix[i][j] = 1;
        else res.matrix[i][j] = 0;
    }
    for(;n;n>>=1){
        if(n&1)res=multi(res,x,p);
        x=multi(x,x,p);
    }
    return res;
}
int main(){
    __int64 p,T,a,b,n;
    __int64 keep1,keep2,keep3;
    __int64 power,result;
    Matrix res;
    scanf("%I64d",&T);
    while(T--){
        scanf("%I64d%I64d%I64d%I64d",&a,&b,&n,&p);
        keep1=(powermod(a,(p-1)/2,p)+1)%p;
        keep2=(powermod(b,(p-1)/2,p)+1)%p;
        if(n==0)power=1;
        else{
             res.matrix[0][0] = 1;
             res.matrix[0][1] = 1;
             res.matrix[1][0] = 1;
             res.matrix[1][1] = 0;
             res=Mat_powermod(res,n-1,p-1);
             power=(res.matrix[0][0]+res.matrix[0][1])%(p-1);
        }
        power+=p-1;
        res.matrix[0][0]=(a+b)%p;
        res.matrix[0][1]=(2*a*b)%p;
        res.matrix[1][0]=2%p;
        res.matrix[1][1]=(a+b)%p;
        res=Mat_powermod(res,power-1,p);
        keep3=(2*(((res.matrix[0][0]*(a+b))%p+(res.matrix[0][1]*2)%p)%p))%p;
        result=1;
        result=(result*keep1)%p;
        result=(result*keep2)%p;
        result=(result*keep3)%p;
        printf("%I64d\n",result);
    }
    return 0;
}