Huawei machine test question hj56 complete number calculation

describe

Perfect number （Perfect number）, Also called perfect number or perfect number , It's some special natural number .

All its real factors （ That is, a divisor other than itself ） And （ Factor function ）, Exactly equal to itself .

for example ：28, It has a divisor 1、2、4、7、14、28, Get rid of it 28 Outside , rest 5 Add up the numbers ,1+2+4+7+14=28.

Input n, Please export n within ( contain n) The number of perfect numbers .

Data range ： 1 \le n \le 5 \times 10^{5} \1≤n≤5×105

Input description ：

Enter a number n

Output description ：

The output does not exceed n The number of perfect numbers of

Example 1

Input ：

1000

Copy output ：

3

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <iostream>
#include <string.h>
#include <algorithm>
#include <vector>
int checkCompletely(int num)                // Check whether the entered number is a perfect number 
{
    std::vector<int> numVect;
    for(int i = 1; i <= num; ++i)
    {
        if(num % i == 0)                  // It means that you can divide 
        {
            numVect.push_back(i);
            numVect.push_back(num / i);
        }
    }

    std::vector<int> tempVect;
    for(int i = 0; i < numVect.size() / 2; ++i)
    {
        tempVect.push_back(numVect.at(i));
    }

    int sum = 0;
    for(int ele : tempVect)
    {
        sum += ele;
    }
    
    if(sum == num * 2)
    {
        return 1;
    }
    else
    {
        return 0;
    }
}

int CompletelyNumber(int number)
{
    int count = 0;
    //1. First find all divisors of each number 
    for(int i = 1; i <= number; ++i)
    {
        int flag = checkCompletely(i);
        if(flag)
        {
            count++;
        }
    }

    return count;
}

int main()
{
    int n;
    while(std::cin >> n)
    {
        int rtn = CompletelyNumber(n);
        std::cout << rtn << std::endl;
    }

    return 0;
}