题解 | #Problem C#

#include <bits/stdc++.h>
using namespace std;
bool isPrime(int n){
    for(int i =2;i<=sqrt(n);i++)
        if(n%i == 0)return false;
    return true;
}
int f(string s){
    int n = stoi(s);
    if(isPrime(n))return n;
    for(int i =2;i<=sqrt(n);i++){
        //分解质因数
        while(n%i == 0){
            n/=i;
        }
    }
    return n;
}
int main() {
    string s;int n;cin>>n;
    while(n--){
        cin>>s;
        for(auto it = s.begin();it!=s.end();){
            if(*it<'0' || *it>'9')it = s.erase(it);
            else it++;
        }
        if(s.length()!=0 && stoi(s)!=0)cout<<f(s)<<endl;
        else cout<<0<<endl;
    }
}

有点难度