717C - Potions Homework - CodeForces Solution

#include <bits/stdc++.h>
#define double long double
#define int long long
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
using namespace std;
typedef pair<int, int> pi;
const int MOD=1000000007;
 
int gcd(int a, int b) {return (b==0? a: gcd(b, a%b));}
int lcm(int a, int b) {return a*b/gcd(a, b);}
 
void yes() {cout << "YES\n"; return;}
void no() {cout << "NO\n"; return;}

int to(string s){
  int n=s.size();
  int i=0;
  while(i<n && s[i]=='0') i++;
  int cnt=s[i]-'0';
  for(i=i+1; i<s.size(); i++){
    cnt*=s[i]-'0';
  }
  return cnt;
}
void solve() {    
  int n;
  cin >> n;
  vector<int> t1(n), t2(n);
  for(int i=0; i<n; i++){
    cin >> t1[i];
    t2[i]=t1[i];
  }
  int cnt=0;
  sort(t1.begin(), t1.end());
  sort(t2.rbegin(), t2.rend());
  for(int i=0; i<n; i++){
    cnt+=t1[i]*t2[i];
    cnt%=10007;
  }
  cout << cnt << "\n";
}
 
signed main() {
  cin.tie(0)->sync_with_stdio(0);
  srand(time(0));
  int t=1;
  // cin >> t;
  //sieve(1e7);
  while(t--){
    solve();
  }
}