~cpp
#include <iostream>
#include <math.h>
using namespace std;
unsigned int factorial_factors(unsigned int);
void main()
{
cout << "2-1000000사이의 숫자를 입력해주세요.조건에 맞지않는 숫자를 입력하면 종료됩니다.\n";
cin >> input_number;
while (1)
{
cout << factorial_factors(input_number) << "\n";
cin >> input_number;
}
}
unsigned int factorial_factors(unsigned int answer)
{
unsigned int *log_answer = (unsigned int*)malloc((answer+2)*sizeof(unsigned int));
unsigned int sum = 1;
unsigned int gab;
unsigned int suchEnd = (unsigned int)sqrt((double)answer);
log_answer[2]=1;
log_answer[3]=0;
for (register unsigned int i=4; i<=answer;i+=2)
{
log_answer[i]=2;
log_answer[i+1]=0;
}
for (register unsigned int i=3; i<=suchEnd; ++i)
{
if (0==log_answer[i])
{
log_answer[i]=1;
gab=i+i;
for(register unsigned int j = i * i; j <= answer; j+= gab)
log_answer[j] = i;
++sum;
}
else
sum+=log_answer[i]=log_answer[i/log_answer[i]]+1;
}
for (register unsigned int i = suchEnd + 1; i <= answer; ++i)
{
if (0==log_answer[i])
{
log_answer[i]=1;
gab=i+i;
++sum;
}
else
sum+=log_answer[i]=log_answer[i/log_answer[i]]+1;
}
free(log_answer);
return sum;
}