Problem p03818 (C++)

Buggy submission (status: Runtime Error):
// g++ temp.cpp
// C++ includes used for precompiling -*- C++ -*-

// Copyright (C) 2003-2013 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file stdc++.h
 *  This is an implementation file for a precompiled header.
 */

// 17.4.1.2 Headers

// C
// #ifndef _GLIBCXX_NO_ASSERT
#include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
/*
//#if __cplusplus >= 201103L
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
*/

// C++
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
/*
//#if __cplusplus >= 201103L
#include <array>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <type_traits>
#include <typeindex>
#include <unordered_map>
#include <unordered_set>
*/
using namespace std;
#define fi first
#define se second
#define repl(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rep(i, n) repl(i, 0, n)
#define each(itr, v) for (auto itr : v)
#define pb(s) push_back(s)
#define maxch(x, y) x = max(x, y)
#define minch(x, y) x = min(x, y)
#define mp(a, b) make_pair(a, b)
#define all(x) (x).begin(), (x).end()
#define dbg(x) cout << #x "=" << x << endl
#define maxch(x, y) x = max(x, y)
#define minch(x, y) x = min(x, y)
#define uni(x) x.erase(unique(all(x)), x.end())
template <class T, class U> inline void chmin(T &t, U f) {
  if (t > f)
    t = f;
}
template <class T, class U> inline void chmax(T &t, U f) {
  if (t < f)
    t = f;
}
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define MIN(a, b) ((a) > (b) ? (b) : (a))

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef pair<P, int> PPI;

#define INF INT_MAX / 3
#define MAX_N 10000
ll n, i, y;
void solve() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> n;
  vector<int> a;
  rep(i, n) cin >> a[i];
  sort(a.begin(), a.end());
  int k = 0;
  rep(i, n - 1) {
    if (a[i] == a[i + 1])
      k++;
  }
  int ans = n - k;
  if (ans % 2 == 1)
    cout << ans << endl;
  else
    cout << ans - 1 << endl;
}
int main() {
  solve();
  return 0;
}

Fixed submission:
// g++ temp.cpp
// C++ includes used for precompiling -*- C++ -*-

// Copyright (C) 2003-2013 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file stdc++.h
 *  This is an implementation file for a precompiled header.
 */

// 17.4.1.2 Headers

// C
// #ifndef _GLIBCXX_NO_ASSERT
#include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
/*
//#if __cplusplus >= 201103L
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
*/

// C++
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
/*
//#if __cplusplus >= 201103L
#include <array>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <type_traits>
#include <typeindex>
#include <unordered_map>
#include <unordered_set>
*/
using namespace std;
#define fi first
#define se second
#define repl(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rep(i, n) repl(i, 0, n)
#define each(itr, v) for (auto itr : v)
#define pb(s) push_back(s)
#define maxch(x, y) x = max(x, y)
#define minch(x, y) x = min(x, y)
#define mp(a, b) make_pair(a, b)
#define all(x) (x).begin(), (x).end()
#define dbg(x) cout << #x "=" << x << endl
#define maxch(x, y) x = max(x, y)
#define minch(x, y) x = min(x, y)
#define uni(x) x.erase(unique(all(x)), x.end())
template <class T, class U> inline void chmin(T &t, U f) {
  if (t > f)
    t = f;
}
template <class T, class U> inline void chmax(T &t, U f) {
  if (t < f)
    t = f;
}
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define MIN(a, b) ((a) > (b) ? (b) : (a))

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef pair<P, int> PPI;

#define INF INT_MAX / 3
#define MAX_N 10000
ll n, i, y;
void solve() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> n;
  vector<int> a(n);
  rep(i, n) cin >> a[i];
  sort(a.begin(), a.end());
  int k = 0;
  rep(i, n - 1) {
    if (a[i] == a[i + 1])
      k++;
  }
  int ans = n - k;
  if (ans % 2 == 1)
    cout << ans << endl;
  else
    cout << ans - 1 << endl;
}
int main() {
  solve();
  return 0;
}