結果
問題 | No.2851 Make Pairs |
ユーザー |
👑 |
提出日時 | 2024-08-25 13:30:56 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 179 ms / 2,000 ms |
コード長 | 2,312 bytes |
コンパイル時間 | 4,053 ms |
コンパイル使用メモリ | 256,904 KB |
最終ジャッジ日時 | 2025-02-24 00:43:53 |
ジャッジサーバーID (参考情報) |
judge1 / judge5 |
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ファイルパターン | 結果 |
---|---|
other | AC * 8 |
ソースコード
#include<bits/stdc++.h>#include<atcoder/all>#define rep(i,n) for(int i=0;i<n;i++)using namespace std;using namespace atcoder;typedef long long ll;typedef vector<int> vi;typedef vector<long long> vl;typedef vector<vector<int>> vvi;typedef vector<vector<long long>> vvl;typedef long double ld;typedef pair<int, int> P;ostream& operator<<(ostream& os, const modint& a) {os << a.val(); return os;}template <int m> ostream& operator<<(ostream& os, const static_modint<m>& a) {os << a.val(); return os;}template <int m> ostream& operator<<(ostream& os, const dynamic_modint<m>& a) {os << a.val(); return os;}template<typename T> istream& operator>>(istream& is, vector<T>& v){int n = v.size(); assert(n > 0); rep(i, n) is >> v[i]; return is;}template<typename U, typename T> ostream& operator<<(ostream& os, const pair<U, T>& p){os << p.first << ' ' << p.second; return os;}template<typename T> ostream& operator<<(ostream& os, const vector<T>& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : " "); returnos;}template<typename T> ostream& operator<<(ostream& os, const vector<vector<T>>& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : "");return os;}template<typename T> ostream& operator<<(ostream& os, const set<T>& se){for(T x : se) os << x << " "; os << "\n"; return os;}template<typename T> ostream& operator<<(ostream& os, const unordered_set<T>& se){for(T x : se) os << x << " "; os << "\n"; return os;}template<typename S, auto op, auto e> ostream& operator<<(ostream& os, const atcoder::segtree<S, op, e>& seg){int n = seg.max_right(0, [](S){returntrue;}); rep(i, n) os << seg.get(i) << (i == n - 1 ? "\n" : " "); return os;}template<typename S, auto op, auto e, typename F, auto mapping, auto composition, auto id> ostream& operator<<(ostream& os, const atcoder::lazy_segtree<S, op, e, F, mapping, composition, id>& seg){int n = seg.max_right(0, [](S){return true;}); rep(i, n) os << seg.get(i) << (i == n -1 ? "\n" : " "); return os;}template<typename T> void chmin(T& a, T b){a = min(a, b);}template<typename T> void chmax(T& a, T b){a = max(a, b);}int main(){int n;cin >> n;map<int, int> ma;rep(i, n){int x;cin >> x;ma[x]++;}int ans = 0;for(auto [key, val] : ma) ans += val / 2;cout << ans << "\n";return 0;}