【分治】魔法石的诱惑

 1 #include <iostream>
 2 
 3 using namespace std;
 4 typedef long long ll;
 5 ll get_minn(ll x)
 6 {
 7     ll ans=0;
 8     while(x>0)
 9     {
10         ans+=x/5;
11         x/=5;
12     }
13     return ans;
14 }
15 int main()
16 {
17     ll q;
18     cin>>q;
19     if(q==0)
20     {
21         cout<<"0"<<endl;
22         return 0;
23     }
24     ll n=0,temp=0;
25     while(temp<q)
26     {
27         n+=5;
28         temp=get_minn(n);
29     }
30     if(temp>q)
31         cout<<"No solution"<<endl;
32     else if(temp==q)
33         cout<<n<<endl;
34 //    cout << "Hello world!" << endl;
35     return 0;
36 }