2957. 统计不同的最简真分数的个数

for(int i = 0;i < T;i++)
{
    cin >> n;
    for(int j = 0;j < n;j++)
    {
        cin >> a;
        S.insert(a);
    }
    int ans = 0;
    while(S.size() > 1)
    {
        auto p = S.begin();
        int t = *p;
        S.erase(p);
        for(auto x : S)
        {
            if(GCD(x,t) == 1)
                ans++;
        }

    }
    cout << "case #" << i << ":" << endl;
    cout << ans << endl;
    S.clear();
}

#include<bits/stdc++.h>
using namespace std;
set<int>S;
int main()
{
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(nullptr);
    int T;cin>>T;
    for(int i=0;i<T;i++){
        int n;cin>>n;
        for(int _=0;_<n;_++){
            int num;cin>>num;
            S.insert(num);
        }
        int ans=0;
        while(S.size()>1){
            set<int>::iterator it=S.begin();
            int p = *it;
            it++;
            for(;it!=S.end();it++){
                if(gcd(p,*it)==1){
                    ans++;
                }   
            }
            S.erase(p);
        }
        cout<<"case #"<<i<<":\n"<<ans<<endl;
        S.clear();
    }
}

#include <bits/stdc++.h>

using namespace std;

int solve(const set<int>& s) {
    int res = 0;
    for (auto i = s.begin(); i != s.end(); ++i) {
        for (auto j = next(i); j != s.end(); ++j) {
            int m = *i, n = *j;
            if (m < n && gcd(m, n) == 1) ++res;
        }
    }
    return res;
}

int main() {
    int T, N, num, n = 0;

    cin >> T;
    while (T--) {
        cin >> N;

        set<int> s;
        while (N--) cin >> num, s.insert(num);
        printf("case #%d:\n%d\n", n++, solve(s));
    }
}

    for(set<int>::iterator iter_i = number_set.begin(); iter_i != number_set.end();iter_i++){
        for(set<int>::iterator iter_j = iter_i;iter_j != number_set.end();iter_j++){
            if(iter_i != iter_j){
                if(getgcd(*iter_i,*iter_j) == 1){
                    count++;
                }
            }
        }
    }
    printf("case #%d:\n",i);
    printf("%d\n",count);
}
return 0;

#include <stdio.h>
#include <stdlib.h>
int gcd(int a, int b)
{
    if(a%b) return gcd(b,a%b);
    else return b;
}
int cmp(const void*a, const void*b)
{
    int *p1=(int*)a, *p2=(int*)b;
    return *p1-*p2;
}
int main()
{
    int T, I;
    scanf("%d",&T);
    for(I=0; I<T; I++)
    {
        int n, i, j, x, num[1000], cnt=0;
        scanf("%d",&n);
        for(i=0; i<n; i++)
        {
            scanf("%d",&num[i]);
            for(j=0; j<i; j++) if(num[j]==num[i]) {n--; i--; break;}
        }
        qsort(num, n, sizeof(int), cmp);
        for(i=0; i<n-1; i++)
            for(j=i+1; j<n; j++)
            {
                if(!(num[i]-num[j])) continue;
                x=gcd(num[j], num[i]);
                if(x==1) cnt++;
            }
        printf("case #%d:\n%d\n",I,cnt);
    }
    return 0;
}

#include <algorithm>
#include <iostream>
#include <numeric>
#include <set>
#include <vector>

using namespace std;

struct Fraction {
    int numerator;
    int denominator;
    bool operator<(Fraction const &frac) const {
        return numerator * frac.denominator < frac.numerator * denominator;
    }
};

int main() {
    ios::sync_with_stdio(false);
    int t;
    cin >> t;
    for (int i = 0; i < t; ++i) {
        int n;
        cin >> n;
        set<Fraction> pool;
        vector<int> nums(n);
        for (auto &i : nums)
            cin >> i;
        sort(nums.begin(), nums.end());
        for (int j = 0; j < n; ++j)
            for (int k = j + 1; k < n; ++k)
                if (gcd(nums[k], nums[j]) == 1)
                    pool.insert({nums[j], nums[k]});
        pool.erase({1, 1});
        cout << "case #" << i << ":\n" << pool.size() << '\n';
    }
}