Cod sursa(job #1768655)

Utilizator bogdi1bogdan bancuta bogdi1 Data 1 octombrie 2016 12:07:35
Problema Factorial Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.51 kb
#include <cstdio>

using namespace std;
long long nr0(int n)
{
    long long r=0;
    while(n>=5){
        r+=n/5;
        n/=5;
    }
    return r;
}
int main()
{   freopen("fact.in", "r",stdin);
    freopen("fact.out", "w",stdout);
    int p,i,pas;
    scanf("%d", &p);
    i=0;
    pas=1<<30;
    while(pas!=0){
        if(i+pas<=1073741824 && nr0(i+pas)<p)
            i+=pas;
        pas/=2;
    }
    if(nr0(i+1)==p)
        printf("%d", i+1);
    else
        printf("-1");
    return 0;
}