[做题记录]数学#1
作者:互联网
万欧 / 类欧
类欧几里得算法
板板。
【模板】类欧几里得算法
#include<bits/stdc++.h>
#define ll long long
#define N 22
#define P 998244353
ll t,p,q,r,l;
struct Po{
ll cntu,cntr,sumi,sums,sqrs,prod;
Po(){cntu = cntr = sumi = sums = sqrs = prod = 0;}
Po operator + (Po b) {
Po c;
c.cntu=(cntu+b.cntu)%P,c.cntr=(cntr+b.cntr)%P;
c.sumi=(sumi+b.sumi+cntr*b.cntr)%P;
c.sums=(sums+b.sums+cntu*b.cntr)%P;
c.sqrs=(sqrs+b.sqrs+((cntu*cntu)%P)*b.cntr+(2*cntu*b.sums)%P)%P;
c.prod=((prod+b.prod+((cntu*cntr)%P)*b.cntr)%P+cntu*b.sumi+cntr*b.sums)%P;
return c;
}
}nu,nr,ans;
inline Po pow(Po a,ll k){
Po res;
while(k){
if(k & 1){res = res + a;}
a = a + a;
k >>= 1;
}
return res;
}
inline ll div(ll a,ll b,ll c,ll d){return ((long double)1.0 * a * b + c) / d;}
inline Po solve(ll p,ll q,ll r,ll l,Po a,Po b){
if(!l)return Po();
if(p >= q)return solve(p % q,q,r,l,a,pow(a,p / q) + b);
ll m = div(l,p,r,q);
if(!m)return pow(b,l);
ll cnt = l - div(q,m,-r - 1,p);
return pow(b,(q - r - 1) / p) + a + solve(q,p,(q - r - 1) % p,m - 1,b,a) + pow(b,cnt);
}
int main(){
scanf("%lld",&t);
while(t -- ){
scanf("%lld%lld%lld%lld",&l,&p,&r,&q);
nu.cntu = 1,nu.cntr = nu.sumi = nu.sums = nu.sqrs = nu.prod = 0;
nr.cntu = nr.sums = nr.sqrs = nr.prod = 0,nr.sumi = nr.cntr = 1;
ans = pow(nu,r / q) + solve(p,q,r % q,l,nu,nr);
printf("%lld %lld %lld\n",(ans.sums+r/q)%P,(ans.sqrs+((r/q)%P)*((r/q)%P))%P,ans.prod);
}
}
万能欧几里得
把其看做\(\sum a^xb^y\)类型。
则可写作矩阵:
\(\begin{bmatrix}\sum_x a^xb^y\\a^xb^y\end{bmatrix}\)\(\begin{bmatrix}1&0\\0&b\end{bmatrix}\)\(\begin{bmatrix}1&a\\0&1\end{bmatrix}\)
那么把\(a,b\)写作矩阵形式也可以
素数
【模板】Pollard-Rho 算法
先判断一个数是否是质数,使用Miller Rabin测试,否则用Pollard Rho算法 找到一个因数,递归操作\(n / p\)和\(p\)。
【模板】Pollard-Rho 算法
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int t;
long long max_factor, n;
long long gcd(long long a, long long b) {
if (b == 0) return a;
return gcd(b, a % b);
}
long long quick_pow(long long x, long long p, long long mod) { //快速幂
long long ans = 1;
while (p) {
if (p & 1) ans = (__int128)ans * x % mod;
x = (__int128)x * x % mod;
p >>= 1;
}
return ans;
}
bool Miller_Rabin(long long p) { //判断素数
if (p < 2) return 0;
if (p == 2) return 1;
if (p == 3) return 1;
long long d = p - 1, r = 0;
while (!(d & 1)) ++r, d >>= 1; //将d处理为奇数
for (long long k = 0; k < 10; ++k) {
long long a = rand() % (p - 2) + 2;
long long x = quick_pow(a, d, p);
if (x == 1 || x == p - 1) continue;
for (int i = 0; i < r - 1; ++i) {
x = (__int128)x * x % p;
if (x == p - 1) break;
}
if (x != p - 1) return 0;
}
return 1;
}
long long Pollard_Rho(long long x) {
long long s = 0, t = 0;
long long c = (long long)rand() % (x - 1) + 1;
int step = 0, goal = 1;
long long val = 1;
for (goal = 1;; goal *= 2, s = t, val = 1) { //倍增优化
for (step = 1; step <= goal; ++step) {
t = ((__int128)t * t + c) % x;
val = (__int128)val * abs(t - s) % x;
if ((step % 127) == 0) {
long long d = gcd(val, x);
if (d > 1) return d;
}
}
long long d = gcd(val, x);
if (d > 1) return d;
}
}
void fac(long long x) {
if (x <= max_factor || x < 2) return;
if (Miller_Rabin(x)) { //如果x为质数
max_factor = max(max_factor, x); //更新答案
return;
}
long long p = x;
while (p >= x) p = Pollard_Rho(x); //使用该算法
while ((x % p) == 0) x /= p;
fac(x), fac(p); //继续向下分解x和p
}
int main() {
scanf("%d", &t);
while (t--) {
srand((unsigned)time(NULL));
max_factor = 0;
scanf("%lld", &n);
fac(n);
if (max_factor == n) //最大的质因数即自己
printf("Prime\n");
else
printf("%lld\n", max_factor);
}
return 0;
}
标签:return,记录,ll,long,cntu,数学,cntr,Po 来源: https://www.cnblogs.com/dixiao/p/15720269.html