Problem p02557 (C++) — buggy submission, verdict: Runtime Error

#include <algorithm>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#define _USE_MATH_DEFINES
#include <cassert>
#include <complex>
#include <functional>
#include <math.h>
using namespace std;

#define rep(i, x) for (ll i = 0; i < x; i++)
#define repn(i, x) for (ll i = 1; i <= x; i++)

typedef long long ll;
const ll INF = 1e17;
const ll MOD = 1000000007;
const ll MAX = 4000001;
const long double eps = 1E-14;

ll max(ll a, ll b) {
  if (a > b) {
    return a;
  }
  return b;
}

ll min(ll a, ll b) {
  if (a > b) {
    return b;
  }
  return a;
}

ll gcd(ll a, ll b) {
  if (b == 0) {
    return a;
  }
  if (a < b) {
    return gcd(b, a);
  }
  return gcd(b, a % b);
}

ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

struct edge {
  ll ind;
  ll fr;
  ll to;
  ll d;
};

class mint {
  long long x;

public:
  mint(long long x = 0) : x((x % MOD + MOD) % MOD) {}
  mint operator-() const { return mint(-x); }
  mint &operator+=(const mint &a) {
    if ((x += a.x) >= MOD)
      x -= MOD;
    return *this;
  }
  mint &operator-=(const mint &a) {
    if ((x += MOD - a.x) >= MOD)
      x -= MOD;
    return *this;
  }
  mint &operator*=(const mint &a) {
    (x *= a.x) %= MOD;
    return *this;
  }
  mint operator+(const mint &a) const {
    mint res(*this);
    return res += a;
  }
  mint operator-(const mint &a) const {
    mint res(*this);
    return res -= a;
  }
  mint operator*(const mint &a) const {
    mint res(*this);
    return res *= a;
  }

  mint pow(ll t) const {
    if (!t)
      return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1)
      a *= *this;
    return a;
  }

  // for prime MOD
  mint inv() const { return pow(MOD - 2); }
  mint &operator/=(const mint &a) { return (*this) *= a.inv(); }
  mint operator/(const mint &a) const {
    mint res(*this);
    return res /= a;
  }

  friend ostream &operator<<(ostream &os, const mint &m) {
    os << m.x;
    return os;
  }
};

mint pw(mint a, ll b) {
  if (b == 0) {
    return 1;
  }
  mint ret = pw(a, b >> 1);
  ret *= ret;
  if (b & 1) {
    ret *= a;
  }
  return ret;
}

typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<vector<vector<ll>>> vvvll;

typedef vector<mint> vmint;
typedef vector<vector<mint>> vvmint;
typedef vector<vector<vector<mint>>> vvvmint;

/////////////////////////////////////
vmint f, finv, inv;

void cominit(ll N) {
  f.assign(N + 1, 1);
  finv.assign(N + 1, 1);
  inv.assign(N + 1, 1);
  inv[1] = 1;

  repn(i, N) {
    f[i] = f[i - 1] * i;
    if (i > 1)
      inv[i] = -inv[MOD % i] * (MOD / i);
    finv[i] = finv[i - 1] * inv[i];
  }
}

mint com(ll a, ll b) {
  if (a < 0 || b < 0 || a < b) {
    return 0;
  }
  return f[a] * finv[b] * finv[a - b];
}

int main() {
  ll N;
  cin >> N;
  vll A(N + 1), B(N + 1);
  repn(i, N) cin >> A[i];
  repn(i, N) cin >> B[i];

  vll acount(N + 1, 0), bcount(N + 1, 0), count(N + 1, 0);
  repn(i, N) {
    acount[A[i]]++;
    bcount[B[i]]++;
  }
  repn(i, N) { count[i] = acount[i] + bcount[i]; }

  repn(i, N) {
    if (count[i] > N) {
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;

  set<pair<ll, ll>> st;
  repn(i, N) if (count[i] > 0) st.insert({count[i], i});

  vvll mat(N + 1);

  repn(i, N) {
    // cout << i << endl;
    if (st.count({count[B[i]], B[i]}))
      st.erase({count[B[i]], B[i]});

    ll x = 0;
    while (1) {
      auto itr = --st.end();
      x = (*itr).second;
      // cout << x << " " << acount[x] << endl;
      st.erase(itr);
      if (acount[x] > 0) {
        break;
      }
    }

    // cout << x << endl;

    mat[x].push_back(B[i]);

    acount[x]--;
    count[x] = acount[x] + bcount[x];
    bcount[B[i]]--;
    count[B[i]] = acount[B[i]] + bcount[B[i]];
    st.insert({count[x], x});
    st.insert({count[B[i]], B[i]});
  }

  repn(i, N) {
    for (ll x : mat[i]) {
      cout << x << " ";
    }
  }
  cout << endl;
}


Error: WA

Fixed submission:

#include <algorithm>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#define _USE_MATH_DEFINES
#include <cassert>
#include <complex>
#include <functional>
#include <math.h>
using namespace std;

#define rep(i, x) for (ll i = 0; i < x; i++)
#define repn(i, x) for (ll i = 1; i <= x; i++)

typedef long long ll;
const ll INF = 1e17;
const ll MOD = 1000000007;
const ll MAX = 4000001;
const long double eps = 1E-14;

ll max(ll a, ll b) {
  if (a > b) {
    return a;
  }
  return b;
}

ll min(ll a, ll b) {
  if (a > b) {
    return b;
  }
  return a;
}

ll gcd(ll a, ll b) {
  if (b == 0) {
    return a;
  }
  if (a < b) {
    return gcd(b, a);
  }
  return gcd(b, a % b);
}

ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

struct edge {
  ll ind;
  ll fr;
  ll to;
  ll d;
};

class mint {
  long long x;

public:
  mint(long long x = 0) : x((x % MOD + MOD) % MOD) {}
  mint operator-() const { return mint(-x); }
  mint &operator+=(const mint &a) {
    if ((x += a.x) >= MOD)
      x -= MOD;
    return *this;
  }
  mint &operator-=(const mint &a) {
    if ((x += MOD - a.x) >= MOD)
      x -= MOD;
    return *this;
  }
  mint &operator*=(const mint &a) {
    (x *= a.x) %= MOD;
    return *this;
  }
  mint operator+(const mint &a) const {
    mint res(*this);
    return res += a;
  }
  mint operator-(const mint &a) const {
    mint res(*this);
    return res -= a;
  }
  mint operator*(const mint &a) const {
    mint res(*this);
    return res *= a;
  }

  mint pow(ll t) const {
    if (!t)
      return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1)
      a *= *this;
    return a;
  }

  // for prime MOD
  mint inv() const { return pow(MOD - 2); }
  mint &operator/=(const mint &a) { return (*this) *= a.inv(); }
  mint operator/(const mint &a) const {
    mint res(*this);
    return res /= a;
  }

  friend ostream &operator<<(ostream &os, const mint &m) {
    os << m.x;
    return os;
  }
};

mint pw(mint a, ll b) {
  if (b == 0) {
    return 1;
  }
  mint ret = pw(a, b >> 1);
  ret *= ret;
  if (b & 1) {
    ret *= a;
  }
  return ret;
}

typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<vector<vector<ll>>> vvvll;

typedef vector<mint> vmint;
typedef vector<vector<mint>> vvmint;
typedef vector<vector<vector<mint>>> vvvmint;

/////////////////////////////////////
vmint f, finv, inv;

void cominit(ll N) {
  f.assign(N + 1, 1);
  finv.assign(N + 1, 1);
  inv.assign(N + 1, 1);
  inv[1] = 1;

  repn(i, N) {
    f[i] = f[i - 1] * i;
    if (i > 1)
      inv[i] = -inv[MOD % i] * (MOD / i);
    finv[i] = finv[i - 1] * inv[i];
  }
}

mint com(ll a, ll b) {
  if (a < 0 || b < 0 || a < b) {
    return 0;
  }
  return f[a] * finv[b] * finv[a - b];
}

int main() {
  ll N;
  cin >> N;
  vll A(N + 1), B(N + 1);
  repn(i, N) cin >> A[i];
  repn(i, N) cin >> B[i];

  vll acount(N + 1, 0), bcount(N + 1, 0), count(N + 1, 0);
  repn(i, N) {
    acount[A[i]]++;
    bcount[B[i]]++;
  }
  repn(i, N) { count[i] = acount[i] + bcount[i]; }

  repn(i, N) {
    if (count[i] > N) {
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;

  set<pair<ll, ll>> st;
  repn(i, N) if (count[i] > 0) st.insert({count[i], i});

  vvll mat(N + 1);

  repn(i, N) {
    // cout << i << endl;
    if (st.count({count[B[i]], B[i]}))
      st.erase({count[B[i]], B[i]});

    ll x = 0;
    while (1) {
      auto itr = --st.end();
      x = (*itr).second;
      // cout << x << " " << acount[x] << endl;
      st.erase(itr);
      if (acount[x] > 0) {
        break;
      }
    }

    // cout << x << endl;

    mat[x].push_back(B[i]);

    acount[x]--;
    count[x] = acount[x] + bcount[x];
    st.insert({count[x], x});
    st.insert({count[B[i]], B[i]});
  }

  repn(i, N) {
    for (ll x : mat[i]) {
      cout << x << " ";
    }
  }
  cout << endl;
}