hdu 4565 So Easy!

来源：互联网发布：python程序调试编辑：程序博客网时间：2024/04/30 20:16
#include"cstdlib"#include"cstdio"#include"cstring"#include"cmath"#include"queue"#include"algorithm"#include"iostream"using namespace std;struct matrix{    __int64 mat[4][4];};matrix matmul(matrix a,matrix b,int n,int m){    int i,j,k;    matrix c;    memset(c.mat,0,sizeof(c.mat));    for(i=0; i<n; i++)    {        for(j=0; j<n; j++)        {            for(k=0; k<n; k++)            {                c.mat[i][j]+=a.mat[i][k]*b.mat[k][j];                c.mat[i][j]%=m;            }        }    }    return c;}matrix matpow(matrix a,int k,int n,int m){    matrix b;    int i;    memset(b.mat,0,sizeof(b.mat));    for(i=0; i<n; i++) b.mat[i][i]=1;    while(k)    {        if(k&1) b=matmul(a,b,n,m);        a=matmul(a,a,n,m);        k>>=1;    }    return b;}int main(){    int x,y,k,m;    while(cin>>x>>y>>k>>m)    {        __int64 aa[123];        matrix a,b,ans;        memset(a.mat,0,sizeof(a.mat));        memset(b.mat,0,sizeof(b.mat));        aa[0]=1%m;        aa[1]=(__int64)ceil(x+sqrt(y*1.0))+m;      //ceil()为向上取整函数        aa[1]%=m;        aa[2]=(__int64)ceil((x+sqrt(y*1.0))*(x+sqrt(y*1.0)))+m;        aa[2]%=m;        if(k<3)        {            printf("%I64d\n",aa[k]);            continue;        }        a.mat[0][0]=aa[2];a.mat[0][1]=aa[1];    //构造矩阵        b.mat[0][0]=2*x;b.mat[0][1]=1;        b.mat[1][0]=y-x*x;        ans=matmul(a,matpow(b,k-2,2,m),2,m);        printf("%I64d\n",(ans.mat[0][0]+m)%m);   //注意负数的情况    }}
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