Problem p02661 (C++) — buggy submission, verdict: Runtime Error

// AtCoder.cpp : このファイルには 'main'
// 関数が含まれています。プログラム実行の開始と終了がそこで行われます。
//

// AtCoder.cpp : このファイルには 'main'
// 関数が含まれています。プログラム実行の開始と終了がそこで行われます。
//

#define _USE_MATH_DEFINES
#include <math.h>

// #include<cmath>

#include <algorithm>
#include <array>
#include <assert.h>
#include <bitset>
#include <chrono>
#include <cmath>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <memory>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_set>
#include <vector>
#pragma GCC optimize("Ofast")

// #include "Ants.h"
using namespace std;
typedef long long ll;
#define rad_to_deg(rad) (((rad) / 2 / M_PI) * 360)
#define EPS (1e-7)
#define INF (1e9)
#define PI (acos(-1))
#define rep(i, n) for (int i = 0; i < n; i++)
#define show(s) cout << s << endl
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
#define LINF (1LL << 50)
#define MOD (1e9 + 7)
#define rep1(i, n) for (int i = 1; i <= n; i++)
#define rrep(i, n) for (int i = n - 1; i >= 0; --i)

typedef pair<ll, ll> P;
ll gcd(ll a, ll b) { // 最大公約数を求める///最大公倍数a*b/gcd(a,b)
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
ll lcd(ll a, ll b) { // 最小公倍数を求める　b=0のときaを返す
  if (b == 0)
    return a;
  return (a / gcd(a, b)) * b;
}
vector<int> divnum(ll num) {
  int dig;
  vector<int> p;
  while (num) {
    dig = num % 10;
    p.push_back(dig);
    num /= 10;
  }
  return p;
}
int digiter(ll num) {
  int dig;
  vector<int> p;
  while (num) {
    dig = num % 10;
    p.push_back(dig);
    num /= 10;
  }
  return p.size();
}
vector<int> convertstring(string s) {
  vector<int> d;
  ll n = s.size();
  rep(i, n) { d.push_back(s[i] - '0'); }
  return d;
}
map<ll, int> prime_factor(ll n) {
  map<ll, int> ret;
  for (ll i = 2; i * i <= n; i++) {
    while (n % i == 0) {
      ret[i]++;
      n /= i;
    }
  }
  if (n != 1)
    ret[n] = 1;
  return ret;
}
vector<ll> divisor(ll n) {
  vector<ll> res;
  for (ll i = 1; i * i <= n; i++) {
    if (n % i != 0)
      continue;
    res.push_back(i);
    if (i * i != n)
      res.push_back(n / i);
  }
  return res;
}

ll myPow(ll x, ll n, ll m) { // x^n
  if (n == 0)
    return 1;
  if (n % 2 == 0)
    return myPow(x * x % m, n / 2, m);
  else
    return x * myPow(x, n - 1, m) % m;
}
std::vector<int> Eratosthenes(const int N) // 素数列挙
{
  std::vector<bool> is_prime(N + 1);
  for (int i = 0; i <= N; i++) {
    is_prime[i] = true;
  }
  std::vector<int> P;
  for (int i = 2; i <= N; i++) {
    if (is_prime[i]) {
      for (int j = 2 * i; j <= N; j += i) {
        is_prime[j] = false;
      }
      P.emplace_back(i);
    }
  }
  return P;
}
const ll mod = MOD;

struct mint {

  ll x; // typedef long long ll;
  mint(ll 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 { return mint(*this) += a; }
  mint operator-(const mint a) const { return mint(*this) -= a; }
  mint operator*(const mint a) const { return mint(*this) *= 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 { return mint(*this) /= a; }
  // operator long long() const { return x; }
};
istream &operator>>(istream &is, const mint &a) { return is >> a.x; }
ostream &operator<<(ostream &os, const mint &a) { return os << a.x; }
struct combination { // comb(a,b)でよぶaCb

  vector<mint> fact, ifact;
  combination(ll n) : fact(n + 1), ifact(n + 1) {
    assert(n < mod);
    fact[0] = 1;
    for (ll i = 1; i <= n; ++i)
      fact[i] = fact[i - 1] * i;
    ifact[n] = fact[n].inv();
    for (ll i = n; i >= 1; --i)
      ifact[i - 1] = ifact[i] * i;
  }
  mint operator()(ll n, ll k) {
    if (k < 0 || k > n)
      return 0;
    return fact[n] * ifact[k] * ifact[n - k];
  }
} comb(1000005); // comb貯め
mint f(ll n, ll k) {
  if (n < 0)
    return 0;
  // nPk = nCk * k!
  mint res = comb(n, k);
  res *= comb.fact[k];
  return res;
}

/*int Q;


struct SegmentTree {
private:
        int n;
        vector<int> node;

public:
        SegmentTree(vector<int> v) {//SegmentTree seg(vector<int>
v(N,INF))で呼び出し int sz = v.size(); n = 1; while (n < sz) n *= 2;
                node.resize(2 * n - 1, INF);
                for (int i = 0; i < sz; i++) node[i + n - 1] = v[i];
                for (int i = n - 2; i >= 0; i--) node[i] = min(node[2 * i + 1],
node[2 * i + 2]);
        }

        void update(int x, int val) {
                x += (n - 1);
                node[x] = val;
                while (x > 0) {
                        x = (x - 1) / 2;
                        node[x] = min(node[2 * x + 1], node[2 * x + 2]);
                }
        }

        int getmin(int a, int b, int k = 0, int l = 0, int r = -1) {
                if (r < 0) r = n;
                if (r <= a || b <= l) return INF;
                if (a <= l && r <= b) return node[k];

                int vl = getmin(a, b, 2 * k + 1, l, (l + r) / 2);
                int vr = getmin(a, b, 2 * k + 2, (l + r) / 2, r);
                return min(vl, vr);
        }
};
// 1-indexedなので注意。
struct BIT {
private:
        vector<int> bit;
        int N;
public:
        BIT(int size) {
                N = size;
                bit.resize(N + 1);
        }

        // 一点更新です
        void add(int a, int w) {//a番目をwに更新
                for (int x = a; x <= N; x += x & -x) bit[x] += w;
        }

        // 1~Nまでの和を求める。
        int sum(int a) {
                int ret = 0;
                for (int x = a; x > 0; x -= x & -x) ret += bit[x];
                return ret;
        }
};*/
/****Union-Ford-Tree***/
int par[int(0x7ffffff)];  // Parent
int Rank[int(0x7ffffff)]; // Deep_of_the_Tree

// int a[100] = { 4,2,3,1,5 }, m[100] ={3,2,2};
// int n = 0;
// const ll mod = 1000000007;

// n要素で初期化
void init(int n) {
  for (int i = 0; i < n; i++) {
    par[i] = i;
    Rank[i] = 0;
  }
}
// 木の根探し
int find(int x) {
  if (par[x] == x) {
    return x;
  } else {
    return par[x] = find(par[x]);
  }
}
// xとyの属する集合を併合
void unite(int x, int y) {
  x = find(x);
  y = find(y);
  if (x == y)
    return;

  if (Rank[x] < Rank[y]) {
    par[x] = y;
  } else {
    par[y] = x;
    if (Rank[x] == Rank[y])
      Rank[x]++;
  }
}

bool same(int x, int y) { return find(x) == find(y); }
/************************************************************************************/
int N;
ll A[200005], B[200005];
vector<P> numA, numB;
int32_t main() {
  cin >> N;
  rep(i, N) cin >> A[i] >> B[i];
  rep(i, N) {
    numA.push_back(P(A[i], B[i]));
    numB.push_back(P(B[i], A[i]));
  }
  sort(A, A + N);
  sort(B, B + N);
  if (N % 2 == 1) {
    ll a = A[N / 2];
    ll b = B[N / 2];
    cout << b - a + 1 << endl;
  } else {
    ll a = A[N / 2 - 1] + A[N / 2];

    ll res = 0;
    ll b = B[N / 2 - 1] + B[N / 2];
    if (a % 2LL == 1LL)
      res++;
    if (b % 2LL == 1LL)
      res++;
    b /= 2LL;
    a = (a + 1LL) / 2LL;
    cout << (b - a) * 2LL + 1LL + res << endl;
  }
}

Error: -11

Fixed submission:

// AtCoder.cpp : このファイルには 'main'
// 関数が含まれています。プログラム実行の開始と終了がそこで行われます。
//

// AtCoder.cpp : このファイルには 'main'
// 関数が含まれています。プログラム実行の開始と終了がそこで行われます。
//

#define _USE_MATH_DEFINES
#include <math.h>

// #include<cmath>

#include <algorithm>
#include <array>
#include <assert.h>
#include <bitset>
#include <chrono>
#include <cmath>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <memory>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_set>
#include <vector>
#pragma GCC optimize("Ofast")

// #include "Ants.h"
using namespace std;
typedef long long ll;
#define rad_to_deg(rad) (((rad) / 2 / M_PI) * 360)
#define EPS (1e-7)
#define INF (1e9)
#define PI (acos(-1))
#define rep(i, n) for (int i = 0; i < n; i++)
#define show(s) cout << s << endl
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
#define LINF (1LL << 50)
#define MOD (1e9 + 7)
#define rep1(i, n) for (int i = 1; i <= n; i++)
#define rrep(i, n) for (int i = n - 1; i >= 0; --i)

typedef pair<ll, ll> P;
ll gcd(ll a, ll b) { // 最大公約数を求める///最大公倍数a*b/gcd(a,b)
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
ll lcd(ll a, ll b) { // 最小公倍数を求める　b=0のときaを返す
  if (b == 0)
    return a;
  return (a / gcd(a, b)) * b;
}
vector<int> divnum(ll num) {
  int dig;
  vector<int> p;
  while (num) {
    dig = num % 10;
    p.push_back(dig);
    num /= 10;
  }
  return p;
}
int digiter(ll num) {
  int dig;
  vector<int> p;
  while (num) {
    dig = num % 10;
    p.push_back(dig);
    num /= 10;
  }
  return p.size();
}
vector<int> convertstring(string s) {
  vector<int> d;
  ll n = s.size();
  rep(i, n) { d.push_back(s[i] - '0'); }
  return d;
}
map<ll, int> prime_factor(ll n) {
  map<ll, int> ret;
  for (ll i = 2; i * i <= n; i++) {
    while (n % i == 0) {
      ret[i]++;
      n /= i;
    }
  }
  if (n != 1)
    ret[n] = 1;
  return ret;
}
vector<ll> divisor(ll n) {
  vector<ll> res;
  for (ll i = 1; i * i <= n; i++) {
    if (n % i != 0)
      continue;
    res.push_back(i);
    if (i * i != n)
      res.push_back(n / i);
  }
  return res;
}

ll myPow(ll x, ll n, ll m) { // x^n
  if (n == 0)
    return 1;
  if (n % 2 == 0)
    return myPow(x * x % m, n / 2, m);
  else
    return x * myPow(x, n - 1, m) % m;
}
std::vector<int> Eratosthenes(const int N) // 素数列挙
{
  std::vector<bool> is_prime(N + 1);
  for (int i = 0; i <= N; i++) {
    is_prime[i] = true;
  }
  std::vector<int> P;
  for (int i = 2; i <= N; i++) {
    if (is_prime[i]) {
      for (int j = 2 * i; j <= N; j += i) {
        is_prime[j] = false;
      }
      P.emplace_back(i);
    }
  }
  return P;
}
const ll mod = MOD;

struct mint {

  ll x; // typedef long long ll;
  mint(ll 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 { return mint(*this) += a; }
  mint operator-(const mint a) const { return mint(*this) -= a; }
  mint operator*(const mint a) const { return mint(*this) *= 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 { return mint(*this) /= a; }
  // operator long long() const { return x; }
};
istream &operator>>(istream &is, const mint &a) { return is >> a.x; }
ostream &operator<<(ostream &os, const mint &a) { return os << a.x; }
struct combination { // comb(a,b)でよぶaCb

  vector<mint> fact, ifact;
  combination(ll n) : fact(n + 1), ifact(n + 1) {
    assert(n < mod);
    fact[0] = 1;
    for (ll i = 1; i <= n; ++i)
      fact[i] = fact[i - 1] * i;
    ifact[n] = fact[n].inv();
    for (ll i = n; i >= 1; --i)
      ifact[i - 1] = ifact[i] * i;
  }
  mint operator()(ll n, ll k) {
    if (k < 0 || k > n)
      return 0;
    return fact[n] * ifact[k] * ifact[n - k];
  }
} comb(1000005); // comb貯め
mint f(ll n, ll k) {
  if (n < 0)
    return 0;
  // nPk = nCk * k!
  mint res = comb(n, k);
  res *= comb.fact[k];
  return res;
}

/*int Q;


struct SegmentTree {
private:
        int n;
        vector<int> node;

public:
        SegmentTree(vector<int> v) {//SegmentTree seg(vector<int>
v(N,INF))で呼び出し int sz = v.size(); n = 1; while (n < sz) n *= 2;
                node.resize(2 * n - 1, INF);
                for (int i = 0; i < sz; i++) node[i + n - 1] = v[i];
                for (int i = n - 2; i >= 0; i--) node[i] = min(node[2 * i + 1],
node[2 * i + 2]);
        }

        void update(int x, int val) {
                x += (n - 1);
                node[x] = val;
                while (x > 0) {
                        x = (x - 1) / 2;
                        node[x] = min(node[2 * x + 1], node[2 * x + 2]);
                }
        }

        int getmin(int a, int b, int k = 0, int l = 0, int r = -1) {
                if (r < 0) r = n;
                if (r <= a || b <= l) return INF;
                if (a <= l && r <= b) return node[k];

                int vl = getmin(a, b, 2 * k + 1, l, (l + r) / 2);
                int vr = getmin(a, b, 2 * k + 2, (l + r) / 2, r);
                return min(vl, vr);
        }
};
// 1-indexedなので注意。
struct BIT {
private:
        vector<int> bit;
        int N;
public:
        BIT(int size) {
                N = size;
                bit.resize(N + 1);
        }

        // 一点更新です
        void add(int a, int w) {//a番目をwに更新
                for (int x = a; x <= N; x += x & -x) bit[x] += w;
        }

        // 1~Nまでの和を求める。
        int sum(int a) {
                int ret = 0;
                for (int x = a; x > 0; x -= x & -x) ret += bit[x];
                return ret;
        }
};*/
/****Union-Ford-Tree***/
int par[int(0x7ffffff)];  // Parent
int Rank[int(0x7ffffff)]; // Deep_of_the_Tree

// int a[100] = { 4,2,3,1,5 }, m[100] ={3,2,2};
// int n = 0;
// const ll mod = 1000000007;

// n要素で初期化
void init(int n) {
  for (int i = 0; i < n; i++) {
    par[i] = i;
    Rank[i] = 0;
  }
}
// 木の根探し
int find(int x) {
  if (par[x] == x) {
    return x;
  } else {
    return par[x] = find(par[x]);
  }
}
// xとyの属する集合を併合
void unite(int x, int y) {
  x = find(x);
  y = find(y);
  if (x == y)
    return;

  if (Rank[x] < Rank[y]) {
    par[x] = y;
  } else {
    par[y] = x;
    if (Rank[x] == Rank[y])
      Rank[x]++;
  }
}

bool same(int x, int y) { return find(x) == find(y); }
/************************************************************************************/
int N;
ll A[100005], B[100005];
int32_t main() {
  cin >> N;
  rep(i, N) cin >> A[i] >> B[i];

  sort(A, A + N);
  sort(B, B + N);
  if (N % 2 == 1) {
    ll a = A[N / 2];
    ll b = B[N / 2];
    cout << b - a + 1 << endl;
  } else {
    ll a = A[N / 2 - 1] + A[N / 2];

    ll res = 0;
    ll b = B[N / 2 - 1] + B[N / 2];
    if (a % 2 == 1)
      res++;
    if (b % 2 == 1)
      res++;
    b /= 2LL;
    a = (a + 1LL) / 2LL;
    cout << b - a + 1LL + res << endl;
  }
}