c - 友好数字函数给出了错误的结果

Question

如this链接描述我必须创建一个代码来计算范围内所有友好数字的总和。我拥有的代码:

#include <stdio.h>

int SumProperDivisors(int Number);

int main(void) {
    //a != b , if d(b) = a ve d(a) = b
    int DividedSum = 0;
    int index = 0;
    int temp = 0;
    int sum = 0;
    for(index = 1; index<10000; index++)
    {
        DividedSum = SumProperDivisors(index); //a
        temp=SumProperDivisors(DividedSum);   //b
        if(DividedSum!=temp)
        {
            if(SumProperDivisors(temp)==DividedSum&&SumProperDivisors(DividedSum)==temp)
            {
            //  printf("%d ",index);
                sum +=index;
                printf("%d ",sum);
            }

        }

    }
    printf("\n\n%d",sum);


    return 0;
}


int SumProperDivisors(int Number)
{
    int index;
    int sum = 0;
    for(index = 1; index < Number; ++index)
    {
        if((Number%index)==0)
        {
            sum += index;
        }
    }
    return sum;
}

产生错误结果 63968，而正确结果应为 31626。我以 friend 的名义问这个问题。那么我做错了什么？

Answer 1

当你找到(220, 284)时，你需要记录你已经找到了284，否则当循环迭代到284时，它会再次找到220。

粗略地说，没有考虑到优化，在 VB 中:

Sub ListAmicablePairs()
    Dim alreadyFound As New List(Of Integer)
    For i = 1 To 9999
        Dim spd1 = SumProperDivisors(i)
        Dim spd2 = SumProperDivisors(spd1)
        If spd2 = i AndAlso spd1 <> i AndAlso Not alreadyFound.Contains(i) Then
            alreadyFound.Add(i)
            alreadyFound.Add(spd1)
            Console.WriteLine("({0}, {1})", i, spd1)
        End If
    Next

    Console.WriteLine(alreadyFound.Sum())

End Sub

输出:

(220, 284)
(1184, 1210)
(2620, 2924)
(5020, 5564)
(6232, 6368)
31626