C++ 程序：求解整数所有约数两两最大公约数之和

#include

using namespace std;

const int N = 110000, P = 10007; int n; int a[N], len; int ans;

void getDivisor() { len = 0; for (int i = 1; i * i <= n; ++i) if (n % i == 0) { a[++len] = i; if (n / i != i) a[++len] = n / i; } }

int gcd(int a, int b) { if (b == 0) { return a; } return gcd(b, a % b); }

int main() { cin >> n; getDivisor(); ans = 0; for (int i = 1; i <= len; ++i) { for (int j = i + 1; j <= len; ++j) { ans = (ans + gcd(a[i], a[j])) % P; } } cout << ans << endl; return 0; }