求大佬修改，悬关

#include<bits/stdc++.h>
#define int long long
using namespace std;
int p,res[510],a[510]={2};
void chen(int A[],int B[],int C[]){
    int la=sizeof(A)/sizeof(A[0]),lb=sizeof(B)/sizeof(B[0]),lc=la+lb;
    for(int i=0;i<la;i++){
        for(int j=0;j<lb;j++){
            C[i+j]+=A[i]*B[j];
            C[i+j+1]+=C[i+j]/10;
            C[i+j]%=10;
        }
    }
}
signed main(){
    cin >>p;
    cout <<(long long)(p*log10(2))+1 <<endl;
    res[0]=1;
    while(p){
        int l[510];
        memset(l,0,sizeof(l));
        if(p&1){
            chen(res,a,l);
            int i=0;
            while(l[i]){
                res[i]=l[i];
                i++;
            }
        }
        memset(l,0,sizeof(l));
        chen(a,a,l);
        int i=0;
        while(l[i]){
            a[i]=l[i];
            i++;
        }
        p>>=1;
    }
    res[0]--;
    for(int i=499;i>=0;i--){
        cout <<res[i];
    }
    return 0;
}