Submission #1191160

#	Time	Username	Problem	Language	Result	Execution time	Memory
1191160		Gray	Diversity (CEOI21_diversity)	C++20	0 / 100	51 ms	45380 KiB

diversity

#include <algorithm>
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define ld long double
#define ff first
#define ss second
#define ln "\n"
#define mp make_pair
#define pb push_back
#define INF (ll)1e18
ll MOD = (ll)(1e9+7);

void solve(){
    ll n, q; cin >> n >> q;
    vector<ll> a(n); map<ll, ll> cnt;
    for (ll i=0; i<n; i++){
        cin >> a[i]; cnt[a[i]]++;
    }
    vector<ll> byc;
    for (auto [x, c]:cnt){
        byc.push_back(c);
    }
    sort(byc.rbegin(), byc.rend());
    ll left=0, right=0, res=0;
    for (ll i=0; i<(ll)byc.size(); i++){
        if (i%2==0){
            res+=n*(n+1)/2-left*(left+1)/2-(n-left-byc[i])*(n-left-byc[i]+1)/2;
            left+=byc[i];
        }else{
            res+=n*(n+1)/2-right*(right+1)/2-(n-right-byc[i])*(n-right-byc[i]+1)/2;
            right+=byc[i];
        }
    }
    cout << res << ln;
}

int main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    #ifdef LOCAL
    auto start = chrono::high_resolution_clock::now();
    #endif
    #ifndef LOCAL
    freopen("cardgame.in", "r", stdin);
    freopen("cardgame.out", "w", stdout);
    #endif
    ll testc=1;
    // cin >> testc;
    for (ll __c=1; __c<=testc; __c++) solve();
    #ifdef LOCAL
    auto duration = chrono::duration_cast<chrono::microseconds>(chrono::high_resolution_clock::now() - start);
    cout << setprecision(0) << fixed << "time: " << (double)duration.count()/1000.0 << " milliseconds" << endl;
    #endif
}

Compilation message (stderr)

diversity.cpp: In function 'int main()':
diversity.cpp:45:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |     freopen("cardgame.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
diversity.cpp:46:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |     freopen("cardgame.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 0 / 10
• Subtask 3: 0 / 8
• Subtask 4: 0 / 16
• Subtask 5: 0 / 26
• Subtask 6: 0 / 36