题解 | #最简真分数#

#include<cstdio>
#include<vector>
using namespace std;
int GDC(int a, int b) {
    if (b == 0) {
        return a;
    } else {
        return GDC(b, a % b);
    }
}
int main() {
    int n ;
    vector<int> arr;
    while (scanf("%d", &n) != EOF) {
        if (n == 0) {
            break;
        }
        for (int i = 0 ; i < n ; ++i) {
            int x;
            scanf("%d", &x);
            arr.push_back(x);
        }
        int len = arr.size();
        int count = 0;
        for (int i = 0 ; i < len - 1; ++i) {
            for (int j = i + 1 ; j < len ; ++j) {
                if (GDC(arr[i], arr[j]) == 1) {
                    ++count;
                } 
            }
        }
        printf("%d\n", count);
    }
    return 0;
}