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#2
rjsp2021-03-15 09:57
你这是秀代码，还是提问。提问的话，你的问题是什么？
以下代码随手瞎写的，仅供参考  程序代码：#include <iostream> #include <string> using namespace std; struct foo { public: foo( unsigned n ) : data_(1,n) { } foo& operator*=( unsigned n ) { unsigned carry = 0; for( auto& c : data_) { carry += c*n; c = carry%10; carry /= 10; } if( carry != 0 ) data_.push_back( carry ); return *this; } foo& operator+=( const foo& b ) { data_.resize( std::max(data_.size(),b.data_.size()) ); unsigned carry = 0; for( size_t i=0; i!=b.data_.size(); ++i ) { carry += data_[i] + b.data_[i]; data_[i] = carry%10; carry /= 10; } if( carry != 0 ) data_.push_back( carry ); return *this; } private: string data_; friend std::ostream& operator<<( std::ostream& os, const foo& f ) { for( auto itor=f.data_.crbegin(); itor!=f.data_.crend(); ++itor ) os << (unsigned)(*itor); return os; } }; foo S( unsigned n ) { foo sum = 0; foo factorial = 1; for( unsigned i=0; i!=n; ++i ) { factorial *= i+1; sum += factorial; } return sum; } int main( void ) { cout << S(1) << endl; cout << S(2) << endl; cout << S(3) << endl; cout << S(50) << endl; } |
#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<string>
using namespace std;
int a[1010000]={},s[1010000]={};
int jc(int a[],int n)
{
memset(a,0,sizeof(a));
a[0]=1;
a[1]=1;
int x;
for(int j=2;j<=n;j++)
{
for(int i=1;i<=a[0];i++)
{
a[i]*=j;
}
for(int i=1;i<=a[0];i++)
{
if(a[i]>=10)
{
a[i+1]+=a[i]/10;
a[i]%=10;
if(i==a[0])a[0]++;
}
}
}
return 0;
}
int jiafa(int s[],int a[])
{
for(int i=1;i<=s[0];i++)
{
s[i]+=a[i];
if(s[i]>9)
{
s[i+1]+=s[i]/10;
s[i]%=10;
}
}
if(s[s[0]+1]!=0)s[0]++;
}
int bijiao(int s[],int a[])
{
if(s[0]>=a[0])return 0;
else return 1;
}
int main()
{
int n;
cin>>n;
for(int i=1;i<=n;i++)
{
jc(a,i);
if(bijiao(s,a))s[0]=a[0];
jiafa(s,a);
}
for(int i=s[0];i>=1;i--)cout<<s[i];
}