改ans为string后仍为30pts
```cpp
#include<iostream>
using namespace std;
string lastnum(string s,int k){
if(s.length()<=k){
while(1){
if(s.length()<k){
s="0"+s;
}
else{
break;
}
}
return s;
}
string res="";
for(int i=s.length()-1;i>s.length()-1-k;i--){
res=s[i]+res;
}
return res;
}
string times(string a,string b){
string c="";
if(a.length()<b.length()){
string t=a;
a=b;
b=t;
}
int x[400]={0};
int alen=a.length();
int blen=b.length();
for(int i=a.length()-1;i>=0;i--){
for(int j=b.length()-1;j>=0;j--){
x[(alen-i)+(blen-j)-1]+=((a[i]-'0')*(b[j]-'0'))%10;
x[(alen-i)+(blen-j)]+=((a[i]-'0')*(b[j]-'0'))/10;
}
}
for(int i=1;i<alen+blen+1;i++){
if(x[i]>9){
x[i+1]+=x[i]/10;
x[i]=x[i]%10;
}
}
int j=0;
for(int i=alen+blen+2;i>0;i--){
if(x[i]!=0){
j=1;
}
if(j==1||i==1){
char num=x[i]+'0';
c=c+num;
}
}
return c;
}
int main(){
int k,x[13];
string ans="1";
string n;
cin>>n>>k;
while(1){
if(n.length()<k){
n="0"+n;
}
else{
break;
}
}
int c=0;
string m,y=lastnum(n,1);
while(1){
c++;
string s=lastnum(n,c);
m=s;
for(int i=0;i<10;i++){
x[i]=0;
}
int t=0;
while(1){
t++;
m=times(m,y);
m=lastnum(m,c);
if(x[m[0]-'0']>0){
char d=t-x[m[0]-'0']+'0';
string f="";
f=f+d;
ans=times(ans,f);
string z;
if(c==1){
y="1";
z=lastnum(n,c);
}
else{
z="1";
}
for(int i=0;i<t-x[m[0]-'0'];i++){
y=times(y,z);
y=lastnum(y,c+2);
if(c!=1&&i==0){
z=lastnum(y,c+2);
}
}
break;
}
x[m[0]-'0']+=t;
}
if(c==k){
break;
}
}
if(lastnum(times(n,y),c)!=lastnum(n,c)){
cout<<-1;
return 0;
}
cout<<ans;
return 0;
}
```
by ABCgfed @ 2023-06-29 10:35:13