# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
1045823 | Sputnik123 | Arranging Shoes (IOI19_shoes) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
#define pb push_back
#define in insert
#define pll pair<ll,ll>
#define vpl vector<pll>
#define vll vector <ll>
#define vl vector<ll>
#define F first
#define ll long long
#define S second
#define all(v) v.begin(),v.end()
#define endl "\n"
#define ull unsigned long long
#define ld long double
using namespace std;
//using namespace __gnu_pbds;
//#pragma GCC optimize("Ofast,unroll-loops")
//#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt,fma")
const ll sz=3e5+5;
const ll inf=1e18;
const ll mod=1e9+7;
const ll mod2=998244353;
const ll eps = 1e-12;
const ll P1=47; // for hashing
const ll P2=41; // for hashing
//template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
//template<class T> using ordered_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;
// ll idx = 1;
void solve()
{
ll n;
cin >> n;
vll a(2 * n);
for(ll i = 0; i < a.size(); i++)
cin >> a[i];
cout << n * (n - 1) / 2 << endl;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
long long t=1;
// cin>>t;
while(t--)
{
// cout << "Case " << (int) idx <<":\n";
solve();
///idx++;
}
}
/*
Note : don`t use fast input in interactive questions
Note : Compare long double with eps = 1e-12
*/