Cod sursa(job #2611060)
Utilizator | Groza Iulia Diana Groza_Iulia_Diana | Data | 6 mai 2020 11:32:47 |
---|---|---|---|
Problema | Factorial | Scor | 25 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.62 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream fin("fact.in");
ofstream fout("fact.out");
int p, nr, c;
int main()
{
fin >> p;
int sol=0, st=1, dr=2000000;
bool ok=0;
while(st<dr)
{
int mij=(st+dr)/2;
nr=0, c=5;
while(c<=mij)
{
nr+=mij/c;
c*=5;
}
c/=5;
if(nr>=p)
dr=mij;
else
st=mij+1;
}
c=5, nr=0;
while(c<=st)
{
nr+=st/c;
c*=5;
}
if(nr==p)
fout << st;
else
fout << -1;
return 0;
}