Problem p01448 (C++) — buggy submission, verdict: Runtime Error

#pragma GCC optimize("O3")
#pragma GCC target("avx")
#include "bits/stdc++.h"

using namespace std;
using ll = long long int;

#define debug(v)                                                               \\
  {                                                                            \\
    printf("L%d %s > ", __LINE__, #v);                                         \\
    cout << (v) << endl;                                                       \\
  }
#define debugv(v)                                                              \\
  {                                                                            \\
    printf("L%d %s > ", __LINE__, #v);                                         \\
    for (auto e : (v)) {                                                       \\
      cout << e << " ";                                                        \\
    }                                                                          \\
    cout << endl;                                                              \\
  }
#define debuga(m, w)                                                           \\
  {                                                                            \\
    printf("L%d %s > ", __LINE__, #m);                                         \\
    for (int x = 0; x < (w); x++) {                                            \\
      cout << (m)[x] << " ";                                                   \\
    }                                                                          \\
    cout << endl;                                                              \\
  }
#define debugaa(m, h, w)                                                       \\
  {                                                                            \\
    printf("L%d %s >\\n", __LINE__, #m);                                        \\
    for (int y = 0; y < (h); y++) {                                            \\
      for (int x = 0; x < (w); x++) {                                          \\
        cout << (m)[y][x] << " ";                                              \\
      }                                                                        \\
      cout << endl;                                                            \\
    }                                                                          \\
  }
#define ALL(v) (v).begin(), (v).end()
#define repeat(cnt, l)                                                         \\
  for (remove_const<decltype(l)>::type cnt = 0; (cnt) < (l); ++(cnt))
#define rrepeat(cnt, l) for (auto cnt = (l)-1; 0 <= (cnt); --(cnt))
#define iterate(cnt, b, e) for (auto cnt = (b); (cnt) != (e); ++(cnt))
#define diterate(cnt, b, e) for (auto cnt = (b); (cnt) != (e); --(cnt))
const ll MD = 1000000007ll;
const long double PI = 3.1415926535897932384626433832795L;
template <typename T1, typename T2>
inline void assert_equal(T1 expected, T2 actual) {
  if (!(expected == actual)) {
    cerr << "assertion fault: expected=" << expected << " actual=" << actual
         << endl;
    abort();
  }
}
template <typename T1, typename T2>
inline void assert_less(T1 actual, T2 threshold) {
  if (!(actual < threshold)) {
    cerr << "assertion fault: " << actual << " < (const)" << threshold << endl;
    abort();
  }
}
template <typename T1, typename T2>
inline void assert_eqless(T1 actual, T2 threshold) {
  if (!(actual <= threshold)) {
    cerr << "assertion fault: " << actual << " <= (const)" << threshold << endl;
    abort();
  }
}
template <typename T1, typename T2>
inline ostream &operator<<(ostream &o, const pair<T1, T2> p) {
  o << '(' << p.first << ':' << p.second << ')';
  return o;
}
template <typename Vec>
inline ostream &_ostream_vecprint(ostream &o, const Vec &p) {
  o << '[';
  for (auto &e : p)
    o << e << ',';
  o << ']';
  return o;
}
template <typename T>
inline ostream &operator<<(ostream &o, const vector<T> &v) {
  return _ostream_vecprint(o, v);
}
template <typename T, size_t S>
inline ostream &operator<<(ostream &o, const array<T, S> &v) {
  return _ostream_vecprint(o, v);
}
template <typename T> inline T &maxset(T &to, const T &val) {
  return to = max(to, val);
}
template <typename T> inline T &minset(T &to, const T &val) {
  return to = min(to, val);
}
void bye(string s, int code = 0) {
  cout << s << endl;
  exit(code);
}
mt19937_64 randdev(8901016);
template <typename T> inline T rand(T l, T h) {
  return uniform_int_distribution<T>(l, h)(randdev);
}
template <> inline double rand<double>(double l, double h) {
  return uniform_real_distribution<double>(l, h)(randdev);
}
template <> inline float rand<float>(float l, float h) {
  return uniform_real_distribution<float>(l, h)(randdev);
}

#if defined(_WIN32) || defined(_WIN64)
#define getchar_unlocked _getchar_nolock
#define putchar_unlocked _putchar_nolock
#elif defined(__GNUC__)
#else
#define getchar_unlocked getchar
#define putchar_unlocked putchar
#endif
namespace {
#define isvisiblechar(c) (0x21 <= (c) && (c) <= 0x7E)
class MaiScanner {
public:
  template <typename T> void input_integer(T &var) {
    var = 0;
    T sign = 1;
    int cc = getchar_unlocked();
    for (; cc < '0' || '9' < cc; cc = getchar_unlocked())
      if (cc == '-')
        sign = -1;
    for (; '0' <= cc && cc <= '9'; cc = getchar_unlocked())
      var = (var << 3) + (var << 1) + cc - '0';
    var = var * sign;
  }
  inline int c() { return getchar_unlocked(); }
  inline MaiScanner &operator>>(int &var) {
    input_integer<int>(var);
    return *this;
  }
  inline MaiScanner &operator>>(long long &var) {
    input_integer<long long>(var);
    return *this;
  }
  inline MaiScanner &operator>>(string &var) {
    int cc = getchar_unlocked();
    for (; !isvisiblechar(cc); cc = getchar_unlocked())
      ;
    for (; isvisiblechar(cc); cc = getchar_unlocked())
      var.push_back(cc);
    return *this;
  }
  template <typename IT> void in(IT begin, IT end) {
    for (auto it = begin; it != end; ++it)
      *this >> *it;
  }
};
class MaiPrinter {
public:
  template <typename T> void output_integer(T var) {
    if (var == 0) {
      putchar_unlocked('0');
      return;
    }
    if (var < 0)
      putchar_unlocked('-'), var = -var;
    char stack[32];
    int stack_p = 0;
    while (var)
      stack[stack_p++] = '0' + (var % 10), var /= 10;
    while (stack_p)
      putchar_unlocked(stack[--stack_p]);
  }
  inline MaiPrinter &operator<<(char c) {
    putchar_unlocked(c);
    return *this;
  }
  inline MaiPrinter &operator<<(int var) {
    output_integer<int>(var);
    return *this;
  }
  inline MaiPrinter &operator<<(long long var) {
    output_integer<long long>(var);
    return *this;
  }
  inline MaiPrinter &operator<<(char *str_p) {
    while (*str_p)
      putchar_unlocked(*(str_p++));
    return *this;
  }
  inline MaiPrinter &operator<<(const string &str) {
    const char *p = str.c_str();
    const char *l = p + str.size();
    while (p < l)
      putchar_unlocked(*p++);
    return *this;
  }
  template <typename IT> void join(IT begin, IT end, char sep = '\\n') {
    for (auto it = begin; it != end; ++it)
      *this << *it << sep;
  }
};
} // namespace
MaiScanner scanner;
MaiPrinter printer;

int imo[100010];

int main() {
  int N;

  scanner >> N;
  // vector<int> imo(N + 2);
  repeat(i, N) {
    int a, b;
    scanner >> a >> b;
    --a;
    imo[a]++;
    imo[min(b, N + 1)]--;
  }
  int best = 0;
  int total = 0;
  repeat(i, N + 2) {
    total += imo[i];
    if (i <= total)
      maxset(best, i);
  }
  printer << best << '\\n';

  return 0;
}


Error: 0

Fixed submission:

#pragma GCC optimize("O3")
#pragma GCC target("avx")
#include "bits/stdc++.h"

using namespace std;
using ll = long long int;

#define debug(v)                                                               \\
  {                                                                            \\
    printf("L%d %s > ", __LINE__, #v);                                         \\
    cout << (v) << endl;                                                       \\
  }
#define debugv(v)                                                              \\
  {                                                                            \\
    printf("L%d %s > ", __LINE__, #v);                                         \\
    for (auto e : (v)) {                                                       \\
      cout << e << " ";                                                        \\
    }                                                                          \\
    cout << endl;                                                              \\
  }
#define debuga(m, w)                                                           \\
  {                                                                            \\
    printf("L%d %s > ", __LINE__, #m);                                         \\
    for (int x = 0; x < (w); x++) {                                            \\
      cout << (m)[x] << " ";                                                   \\
    }                                                                          \\
    cout << endl;                                                              \\
  }
#define debugaa(m, h, w)                                                       \\
  {                                                                            \\
    printf("L%d %s >\\n", __LINE__, #m);                                        \\
    for (int y = 0; y < (h); y++) {                                            \\
      for (int x = 0; x < (w); x++) {                                          \\
        cout << (m)[y][x] << " ";                                              \\
      }                                                                        \\
      cout << endl;                                                            \\
    }                                                                          \\
  }
#define ALL(v) (v).begin(), (v).end()
#define repeat(cnt, l)                                                         \\
  for (remove_const<decltype(l)>::type cnt = 0; (cnt) < (l); ++(cnt))
#define rrepeat(cnt, l) for (auto cnt = (l)-1; 0 <= (cnt); --(cnt))
#define iterate(cnt, b, e) for (auto cnt = (b); (cnt) != (e); ++(cnt))
#define diterate(cnt, b, e) for (auto cnt = (b); (cnt) != (e); --(cnt))
const ll MD = 1000000007ll;
const long double PI = 3.1415926535897932384626433832795L;
template <typename T1, typename T2>
inline void assert_equal(T1 expected, T2 actual) {
  if (!(expected == actual)) {
    cerr << "assertion fault: expected=" << expected << " actual=" << actual
         << endl;
    abort();
  }
}
template <typename T1, typename T2>
inline void assert_less(T1 actual, T2 threshold) {
  if (!(actual < threshold)) {
    cerr << "assertion fault: " << actual << " < (const)" << threshold << endl;
    abort();
  }
}
template <typename T1, typename T2>
inline void assert_eqless(T1 actual, T2 threshold) {
  if (!(actual <= threshold)) {
    cerr << "assertion fault: " << actual << " <= (const)" << threshold << endl;
    abort();
  }
}
template <typename T1, typename T2>
inline ostream &operator<<(ostream &o, const pair<T1, T2> p) {
  o << '(' << p.first << ':' << p.second << ')';
  return o;
}
template <typename Vec>
inline ostream &_ostream_vecprint(ostream &o, const Vec &p) {
  o << '[';
  for (auto &e : p)
    o << e << ',';
  o << ']';
  return o;
}
template <typename T>
inline ostream &operator<<(ostream &o, const vector<T> &v) {
  return _ostream_vecprint(o, v);
}
template <typename T, size_t S>
inline ostream &operator<<(ostream &o, const array<T, S> &v) {
  return _ostream_vecprint(o, v);
}
template <typename T> inline T &maxset(T &to, const T &val) {
  return to = max(to, val);
}
template <typename T> inline T &minset(T &to, const T &val) {
  return to = min(to, val);
}
void bye(string s, int code = 0) {
  cout << s << endl;
  exit(code);
}
mt19937_64 randdev(8901016);
template <typename T> inline T rand(T l, T h) {
  return uniform_int_distribution<T>(l, h)(randdev);
}
template <> inline double rand<double>(double l, double h) {
  return uniform_real_distribution<double>(l, h)(randdev);
}
template <> inline float rand<float>(float l, float h) {
  return uniform_real_distribution<float>(l, h)(randdev);
}

#if defined(_WIN32) || defined(_WIN64)
#define getchar_unlocked _getchar_nolock
#define putchar_unlocked _putchar_nolock
#elif defined(__GNUC__)
#else
#define getchar_unlocked getchar
#define putchar_unlocked putchar
#endif
namespace {
#define isvisiblechar(c) (0x21 <= (c) && (c) <= 0x7E)
class MaiScanner {
public:
  template <typename T> void input_integer(T &var) {
    var = 0;
    T sign = 1;
    int cc = getchar_unlocked();
    for (; cc < '0' || '9' < cc; cc = getchar_unlocked())
      if (cc == '-')
        sign = -1;
    for (; '0' <= cc && cc <= '9'; cc = getchar_unlocked())
      var = (var << 3) + (var << 1) + cc - '0';
    var = var * sign;
  }
  inline int c() { return getchar_unlocked(); }
  inline MaiScanner &operator>>(int &var) {
    input_integer<int>(var);
    return *this;
  }
  inline MaiScanner &operator>>(long long &var) {
    input_integer<long long>(var);
    return *this;
  }
  inline MaiScanner &operator>>(string &var) {
    int cc = getchar_unlocked();
    for (; !isvisiblechar(cc); cc = getchar_unlocked())
      ;
    for (; isvisiblechar(cc); cc = getchar_unlocked())
      var.push_back(cc);
    return *this;
  }
  template <typename IT> void in(IT begin, IT end) {
    for (auto it = begin; it != end; ++it)
      *this >> *it;
  }
};
class MaiPrinter {
public:
  template <typename T> void output_integer(T var) {
    if (var == 0) {
      putchar_unlocked('0');
      return;
    }
    if (var < 0)
      putchar_unlocked('-'), var = -var;
    char stack[32];
    int stack_p = 0;
    while (var)
      stack[stack_p++] = '0' + (var % 10), var /= 10;
    while (stack_p)
      putchar_unlocked(stack[--stack_p]);
  }
  inline MaiPrinter &operator<<(char c) {
    putchar_unlocked(c);
    return *this;
  }
  inline MaiPrinter &operator<<(int var) {
    output_integer<int>(var);
    return *this;
  }
  inline MaiPrinter &operator<<(long long var) {
    output_integer<long long>(var);
    return *this;
  }
  inline MaiPrinter &operator<<(char *str_p) {
    while (*str_p)
      putchar_unlocked(*(str_p++));
    return *this;
  }
  inline MaiPrinter &operator<<(const string &str) {
    const char *p = str.c_str();
    const char *l = p + str.size();
    while (p < l)
      putchar_unlocked(*p++);
    return *this;
  }
  template <typename IT> void join(IT begin, IT end, char sep = '\\n') {
    for (auto it = begin; it != end; ++it)
      *this << *it << sep;
  }
};
} // namespace
MaiScanner scanner;
MaiPrinter printer;

int main() {
  int N;

  scanner >> N;
  vector<int> imo(N + 2);
  repeat(i, N) {
    int a, b;
    scanner >> a >> b;
    --a;
    imo[a]++;
    imo[min(b, N + 1)]--;
  }
  int best = 0;
  int total = 0;
  repeat(i, N + 2) {
    total += imo[i];
    if (i <= total)
      maxset(best, i);
  }
  printer << best << '\\n';

  return 0;
}