Cod sursa(job #2885296)

Utilizator matwudemagogul matwu Data 5 aprilie 2022 19:44:58
Problema Factorial Scor 0
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 0.74 kb
#include <bits/stdc++.h>
using namespace std;

ifstream fin("fact.in");
ofstream fout("fact.out");
unsigned long long desc(unsigned long long k1){
    unsigned long long sum = 0;
    while(k1 >= 5){
        k1 /= 5;
        sum += k1;
    }
    return sum;
}

int n;
unsigned long long st = 0, dr = 99999999999, gasit = 0, mij, k;

int main(){

    fin >> n;
    while(st <= dr && gasit == 0){
        mij = (st + dr) / 2;
        k = desc(mij);
        fout << mij  << " " << k << '\n';
        
        if(n == k) gasit = mij;
        else if(n < k) dr = mij - 1;
        else st = mij + 1;
    }
    for(long long i = gasit; i >= 1; i--)
        if(i % 5 == 0){
            fout << i;
            return 0;
        }
}