NOIP2017模拟赛 k-斐波（数学+欧几里得+矩阵乘法）

水题 复习 扩欧&矩阵乘法
扩欧注意最终取模！
关于数学的题如果没有超过空间那么尽量开longlong

代码

#include<iostream>#include<algorithm>#include<cstdio>#include<queue>#include<cmath>#include<cstring>using namespace std;#define int long longtypedef int arr[3][3];arr a,ans,temp;int n,p;void cheng(arr a,arr b){    int i,j,k;    memset(temp,0,sizeof(temp));    for(i=1;i<=2;i++){        for(j=1;j<=2;j++){            for(k=1;k<=2;k++){                temp[i][j]=(temp[i][j]+a[i][k]*b[k][j])%p;            }        }    }    memcpy(a,temp,sizeof(temp));}int ksm(int y){    if(y==1||y==0) return 1;    while(y)    {        if(y&1) cheng(ans,a);        y>>=1;        cheng(a,a);    }    return (ans[1][1]+ans[2][1])%p;}int gcd(int a,int b,int &x,int &y){    if(b==0){x=1;y=0;return a;    }    int r=gcd(b,a%b,x,y);    int tmp;    tmp=x;x=y;y=tmp-a/b*y;    return r;}main(){//  freopen("kfib.in","r",stdin);//  freopen("kfib.out","w",stdout);    int i,j;    ans[1][1]=ans[2][2]=1;    a[1][2]=a[2][1]=a[2][2]=1;    scanf("%lld%lld",&n,&p);    int x,y;    int an=ksm(n);    int r=gcd(an,p,x,y);    int cnt=0;    if(p==1){if(n==1) cout<<1;     else cout<<"None";     return 0;     }    if(an%p==0){        cout<<"None";        return 0;    }    x=(x+p)%p;    cout<<x;    return 0;}