Problem p03735 (C++)

Buggy submission (status: Runtime Error):
/*
СТРОИМ СТЕНУ РАБОТЯГИ!
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*/
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

template <typename T1, typename T2> inline void chkmin(T1 &x, T2 y) {
  if (x > y)
    x = y;
}
template <typename T1, typename T2> inline void chkmax(T1 &x, T2 y) {
  if (x < y)
    x = y;
}
/** Interface */

inline int readChar();
template <class T = int> inline T readInt();
template <class T> inline void writeInt(T x, char end = 0);
inline void writeChar(int x);
inline void writeWord(const char *s);

/** Read */

static const int buf_size = 4096;

inline int getChar() {
  static char buf[buf_size];
  static int len = 0, pos = 0;
  if (pos == len) {
    pos = 0, len = fread(buf, 1, buf_size, stdin);
  }
  if (pos == len) {
    return -1;
  }
  return buf[pos++];
}

inline int readChar() {
  int c = getChar();
  while (c <= 32) {
    c = getChar();
  }
  return c;
}

template <class T> inline T readInt() {
  int s = 1, c = readChar();
  T x = 0;
  if (c == '-')
    s = -1, c = getChar();
  while ('0' <= c && c <= '9')
    x = x * 10 + c - '0', c = getChar();
  return s == 1 ? x : -x;
}

/** Write */

static int write_pos = 0;
static char write_buf[buf_size];

inline void writeChar(int x) {
  if (write_pos == buf_size)
    fwrite(write_buf, 1, buf_size, stdout), write_pos = 0;
  write_buf[write_pos++] = x;
}

template <class T> inline void writeInt(T x, char end) {
  if (x < 0)
    writeChar('-'), x = -x;

  char s[24];
  int n = 0;
  while (x || !n)
    s[n++] = '0' + x % 10, x /= 10;
  while (n--)
    writeChar(s[n]);
  if (end)
    writeChar(end);
}

inline void writeWord(const char *s) {
  while (*s)
    writeChar(*s++);
}

struct Flusher {
  ~Flusher() {
    if (write_pos)
      fwrite(write_buf, 1, write_pos, stdout), write_pos = 0;
  }
} flusher;

using namespace std;

#define sz(c) (int)(c).size()
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define left left228
#define right right228
#define next next228
#define rank rank228
#define prev prev228
const int MAXN = 100001;
const int INF = 1000000000;

int n;
long long rmax, bmax, bmin = INF, rmin = INF;
pair<long long, long long> ar[MAXN];

int main() {
  n = readInt();
  for (int i = 1; i <= n; i++) {
    ar[i].first = readInt(), ar[i].second = readInt();
    if (ar[i].first > ar[i].second) {
      swap(ar[i].first, ar[i].second);
    }
  }
  sort(ar + 1, ar + n + 1);
  for (int i = 1; i <= n; i++) {
    chkmax(rmax, ar[i].first);
    chkmin(rmin, ar[i].first);
    chkmax(bmax, ar[i].second);
    chkmin(bmin, ar[i].second);
  }
  long long ans = (ar[n].first - ar[1].first) * (bmax - bmin);
  rmax = bmax, bmin = ar[2].first;
  long long l = INF, r = ar[n].first;
  for (int i = 1; i < n; i++) {
    chkmin(l, ar[i].second);
    chkmax(r, ar[i].second);
    chkmin(ans, 1LL * (rmax - rmin) * (r - min(l, ar[i + 1].first)));
  }
  cout << ans << '\n';
  return 0;
}


Fixed submission:
/*
СТРОИМ СТЕНУ РАБОТЯГИ!
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*/
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

template <typename T1, typename T2> inline void chkmin(T1 &x, T2 y) {
  if (x > y)
    x = y;
}
template <typename T1, typename T2> inline void chkmax(T1 &x, T2 y) {
  if (x < y)
    x = y;
}
/** Interface */

inline int readChar();
template <class T = int> inline T readInt();
template <class T> inline void writeInt(T x, char end = 0);
inline void writeChar(int x);
inline void writeWord(const char *s);

/** Read */

static const int buf_size = 4096;

inline int getChar() {
  static char buf[buf_size];
  static int len = 0, pos = 0;
  if (pos == len) {
    pos = 0, len = fread(buf, 1, buf_size, stdin);
  }
  if (pos == len) {
    return -1;
  }
  return buf[pos++];
}

inline int readChar() {
  int c = getChar();
  while (c <= 32) {
    c = getChar();
  }
  return c;
}

template <class T> inline T readInt() {
  int s = 1, c = readChar();
  T x = 0;
  if (c == '-')
    s = -1, c = getChar();
  while ('0' <= c && c <= '9')
    x = x * 10 + c - '0', c = getChar();
  return s == 1 ? x : -x;
}

/** Write */

static int write_pos = 0;
static char write_buf[buf_size];

inline void writeChar(int x) {
  if (write_pos == buf_size)
    fwrite(write_buf, 1, buf_size, stdout), write_pos = 0;
  write_buf[write_pos++] = x;
}

template <class T> inline void writeInt(T x, char end) {
  if (x < 0)
    writeChar('-'), x = -x;

  char s[24];
  int n = 0;
  while (x || !n)
    s[n++] = '0' + x % 10, x /= 10;
  while (n--)
    writeChar(s[n]);
  if (end)
    writeChar(end);
}

inline void writeWord(const char *s) {
  while (*s)
    writeChar(*s++);
}

struct Flusher {
  ~Flusher() {
    if (write_pos)
      fwrite(write_buf, 1, write_pos, stdout), write_pos = 0;
  }
} flusher;

using namespace std;

#define sz(c) (int)(c).size()
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define left left228
#define right right228
#define next next228
#define rank rank228
#define prev prev228
const int MAXN = 200001;
const int INF = 1000000000;

int n;
long long rmax, bmax, bmin = INF, rmin = INF;
pair<long long, long long> ar[MAXN];

int main() {
  n = readInt();
  for (int i = 1; i <= n; i++) {
    ar[i].first = readInt(), ar[i].second = readInt();
    if (ar[i].first > ar[i].second) {
      swap(ar[i].first, ar[i].second);
    }
  }
  sort(ar + 1, ar + n + 1);
  for (int i = 1; i <= n; i++) {
    chkmax(rmax, ar[i].first);
    chkmin(rmin, ar[i].first);
    chkmax(bmax, ar[i].second);
    chkmin(bmin, ar[i].second);
  }
  long long ans = (ar[n].first - ar[1].first) * (bmax - bmin);
  rmax = bmax, bmin = ar[2].first;
  long long l = INF, r = ar[n].first;
  for (int i = 1; i < n; i++) {
    chkmin(l, ar[i].second);
    chkmax(r, ar[i].second);
    chkmin(ans, 1LL * (rmax - rmin) * (r - min(l, ar[i + 1].first)));
  }
  cout << ans << '\n';
  return 0;
}