// Let d(n) be defined as the sum of proper divisors of n (numbers less than n which divide evenly into n). // If d(a) = b and d(b) = a, where a b, then a and b are an amicable pair and each of a and b are called amicable numbers. // // For example, the proper divisors of 220 are 1, 2, 4, 5, 10, 11, 20, 22, 44, 55 and 110; therefore d(220) = 284. The proper divisors of 284 are 1, 2, 4, 71 and 142; so d(284) = 220. // // Evaluate the sum of all the amicable numbers under 10000. #include <iostream> #include <windows.h> using namespace std; const int MAX_NUM = 10000; int number[MAX_NUM + 1]; //获取某数亲和数 int GetAmicableNum(int num) { //寻找此数的亲和数 int amicableNum = 0; for(int i = num / 2; i >= 1; i--) { if(num % i == 0) { amicableNum += i; } } //记录此数的亲和数 number[num] = amicableNum; //返回亲和数 return amicableNum; } void F1() { cout << "void F1()" << endl; LARGE_INTEGER timeStart, timeEnd, freq; QueryPerformanceFrequency(&freq); QueryPerformanceCounter(&timeStart); int result = 0; //亲和数的数目 int tempAmicableNum = 0; for(int i = 1; i <= MAX_NUM; i++) { tempAmicableNum = GetAmicableNum(i); //是亲和数 if(tempAmicableNum <= MAX_NUM && number[tempAmicableNum] == i && tempAmicableNum != i) { cout << number[i] << " " << i << endl; result += i + tempAmicableNum; } } cout << MAX_NUM << "以内的亲和数之和为" << result << endl; QueryPerformanceCounter(&timeEnd); cout << "Total Milliseconds is " << (double)((double)(timeEnd.QuadPart - timeStart.QuadPart) * 1000 / (double)freq.QuadPart) << endl; } //主函数 int main() { F1(); return 0; } /* void F1() 220 284 1184 1210 2620 2924 5020 5564 6232 6368 10000以内的亲和数之和为31626 Total Milliseconds is 216.438 By GodMoon */