dev里可以啊！！！

xkm0606 @ 2024-12-02 20:24:39

#include <bits/stdc++.h>
using namespace std;
int main()
{
    double a,c=1,d=0;
    cin>>a;
    for(int i=a;i>0;i--)
    {
        for(int r=i;r>0;r--)
        {
            c=c*r;
        }
        d+=c;
        c=1;
    }
    printf("%.0f",d);
}

by _Sky_Dream_ @ 2024-12-02 20:26:11

@xkm0606

别开double开longlong

by xkm0606 @ 2024-12-03 19:38:36

用longlong分更低了

分数

by sdvfduhufh @ 2024-12-07 12:14:20

@xkm0606@xkm0606用高精

by sdvfduhufh @ 2024-12-07 12:15:09

@sdvfduhufh超long long了

by sdvfduhufh @ 2024-12-07 12:15:52

#include<bits/stdc++.h>
using namespace std;
string add(string& a,string& b) 
{
    string ans;
    int x=0,i=a.size()-1,j=b.size()-1;
    while(i>=0||j>=0){
        int c1=i>=0? a[i--]-'0':0;
        int c2=j>=0? b[j--]-'0':0;
        x+=c1+c2;
        ans+=x%10+'0';
        x/=10;
    } 
    if(x) ans+="1";
    reverse(ans.begin(),ans.end());
    a=ans;
    return ans;
}
string mul(string& a,string &b)
{
    if(a=="0"||b=="0") return "0";
    int x=0,l1=a.size(),l2=b.size();
    string ans(l1+l2-1,'0');
    for(int i=l1-1;i>=0;i--)
    {
        x=0;
        for(int j=l2-1;j>=0;j--)
        {
            int c1=a[i]-'0',c2=b[j]-'0';
            x+=c1*c2+ans[i+j]-'0';
            ans[i+j]=x%10+'0';
            x/=10; 
        }
        if(i) ans[i-1] +=x;
    }
    if(x) ans=to_string(x)+ans;
    return ans;
}

by litianrui0201 @ 2024-12-14 23:07:01

油题