分块打表

最新推荐文章于 2024-07-09 11:28:24 发布

Lazines_by

最新推荐文章于 2024-07-09 11:28:24 发布

阅读量752

点赞数

CC 4.0 BY-SA版权

分类专栏：其他

本文链接：https://blog.youkuaiyun.com/xiaolonggezte/article/details/72821647

其他专栏收录该内容

10 篇文章

订阅专栏

本文介绍了一种处理大数阶乘模运算的方法，针对n达到10^9规模的问题，采用预处理技术来避免超时。通过将大数分解并利用预先计算好的部分结果进行快速求解。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

n ! % p的问题，当n 为10^9的时候，直接遍历会超时，需要打表预处理。

打表程序：

#include<iostream>
#include<cstdio>
#define lon long long
using namespace std;
const int maxn=110;
lon n,p,a[maxn];
int main()
{
    freopen("1.out","w",stdout);lon ans=1;
    for(lon i=0;i<=1000000007;i+=10000000)
    {
        for(lon j=i+1;j<=i+10000000;j++)
        ans=(ans*j)%1000000007;
        cout<<ans<<",";
    }
    return 0;
}

#include<iostream>
#include<cstdio>
#define lon long long
using namespace std;
lon n,p;
lon a[110]={1,682498929,491101308,76479948,723816384,67347853,27368307,
625544428,199888908,888050723,927880474,281863274,661224977,623534362,
970055531,261384175,195888993,66404266,547665832,109838563,933245637,
724691727,368925948,268838846,136026497,112390913,135498044,217544623,
419363534,500780548,668123525,128487469,30977140,522049725,309058615,
386027524,189239124,148528617,940567523,917084264,429277690,996164327,
358655417,568392357,780072518,462639908,275105629,909210595,99199382,
703397904,733333339,97830135,608823837,256141983,141827977,696628828,
637939935,811575797,848924691,131772368,724464507,272814771,326159309,
456152084,903466878,92255682,769795511,373745190,606241871,825871994,
957939114,435887178,852304035,663307737,375297772,217598709,624148346,
671734977,624500515,748510389,203191898,423951674,629786193,672850561,
814362881,823845496,116667533,256473217,627655552,245795606,586445753,
172114298,193781724,778983779,83868974,315103615,965785236,492741665,
377329025,847549272,698611116};
int main()
{
     lon now=n/10000000;
     lon ans=a[now];
     for(lon i=now*10000000+1;i<=n;i++)
     ans=ans*i%p;
     cout<<ans%p;
     return 0;

}