Problem p03688 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
using namespace std;
/*{{{*/ // template
#define rep(i, n) for (int i = 0; i < n; i++)
constexpr int INF = numeric_limits<int>::max() / 2;
constexpr long long LINF = numeric_limits<long long>::max() / 3;
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define all(v) (v).begin(), (v).end()
#define sz(x) (int)(x).size()
#define debug(x) cerr << #x << ":" << x << endl
#define debug2(x, y) cerr << #x << "," << #y ":" << x << "," << y << endl
// struct fin{ fin(){ cin.tie(0); ios::sync_with_stdio(false); } } fin_;
struct Double {
  double d;
  explicit Double(double x) : d(x) {}
};
ostream &operator<<(ostream &os, const Double x) {
  os << fixed << setprecision(20) << x.d;
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) {
  os << "[";
  for (const auto &v : vec) {
    os << v << ",";
  }
  os << "]";
  return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
  os << "(" << p.first << "," << p.second << ")";
  return os;
}
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}
// constexpr double eps = 1e-14;
constexpr double eps = 1e-10;
constexpr ll mod = 1e9 + 7;
const int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};
/*}}}*/

int N;
vector<int> a;

int main() {
  cin >> N;
  a.resize(N);
  rep(i, N) cin >> a[i];
  sort(all(a));
  reverse(all(a));

  if (a[0] == N - 1 and a[N - 1] == N - 1) {
    cout << "Yes" << endl;
    return 0;
  }

  if (a[0] - a[N - 1] > 1) {
    cout << "No" << endl;
    return 0;
  }

  if (a[0] - a[N - 1] == 1) {
    int mn = a[N - 1];
    int mx = a[0];
    int mnn = 0, mxn = 0;
    rep(i, N) if (a[i] == mn) mnn++;
    rep(i, N) if (a[i] == mx) mxn++;

    int unused = N - mx;

    int use = mx - mnn;
    // cout << use << endl;
    if (use == 0) {
      assert(false);
      cout << "No" << endl;
      return 0;
    }

    if (unused < use) {
      cout << "No" << endl;
      return 0;
    }

    int t = use + unused;
    if (mxn != t) {
      cout << "No" << endl;
      return 0;
    }

    cout << "Yes" << endl;
  } else {
    if (N >= a[0] * 2) {
      cout << "Yes" << endl;
    } else {
      cout << "No" << endl;
    }
  }
}


Fixed submission:
#include <bits/stdc++.h>
using namespace std;
/*{{{*/ // template
#define rep(i, n) for (int i = 0; i < n; i++)
constexpr int INF = numeric_limits<int>::max() / 2;
constexpr long long LINF = numeric_limits<long long>::max() / 3;
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define all(v) (v).begin(), (v).end()
#define sz(x) (int)(x).size()
#define debug(x) cerr << #x << ":" << x << endl
#define debug2(x, y) cerr << #x << "," << #y ":" << x << "," << y << endl
// struct fin{ fin(){ cin.tie(0); ios::sync_with_stdio(false); } } fin_;
struct Double {
  double d;
  explicit Double(double x) : d(x) {}
};
ostream &operator<<(ostream &os, const Double x) {
  os << fixed << setprecision(20) << x.d;
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) {
  os << "[";
  for (const auto &v : vec) {
    os << v << ",";
  }
  os << "]";
  return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
  os << "(" << p.first << "," << p.second << ")";
  return os;
}
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}
// constexpr double eps = 1e-14;
constexpr double eps = 1e-10;
constexpr ll mod = 1e9 + 7;
const int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};
/*}}}*/

int N;
vector<int> a;

int main() {
  cin >> N;
  a.resize(N);
  rep(i, N) cin >> a[i];
  sort(all(a));
  reverse(all(a));

  if (a[0] == N - 1 and a[N - 1] == N - 1) {
    cout << "Yes" << endl;
    return 0;
  }

  if (a[0] - a[N - 1] > 1) {
    cout << "No" << endl;
    return 0;
  }

  if (a[0] - a[N - 1] == 1) {
    int mn = a[N - 1];
    int mx = a[0];
    int mnn = 0, mxn = 0;
    rep(i, N) if (a[i] == mn) mnn++;
    rep(i, N) if (a[i] == mx) mxn++;

    int unused = N - mx;

    int use = mx - mnn;
    // cout << use << endl;
    if (use <= 0) {
      cout << "No" << endl;
      return 0;
    }

    if (unused < use) {
      cout << "No" << endl;
      return 0;
    }

    int t = use + unused;
    if (mxn != t) {
      cout << "No" << endl;
      return 0;
    }

    cout << "Yes" << endl;
  } else {
    if (N >= a[0] * 2) {
      cout << "Yes" << endl;
    } else {
      cout << "No" << endl;
    }
  }
}