Problem p02945 (C++)

Buggy submission (status: Time Limit Exceeded):
// #pragma GCC optimize("O3", "unroll-loops")
// #pragma GCC target("avx2")
#include <bits/stdc++.h>
#define FAST                                                                   \
  ios_base::sync_with_stdio(0);                                                \
  cin.tie(0);                                                                  \
  cout.tie(0)
#define FIXED cout << fixed << setprecision(12)
#define RANDOM srand(94385)
#define all(a) a.begin(), a.end()
#define shuffle(a)                                                             \
  for (int i = 0; i < sz(a); ++i)                                              \
    swap(a[i], a[rand() % sz(a)]);
#define enter puts("")
#define space putchar(' ')
#define Mem(a, x) memset(a, x, sizeof(a))
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

void debug_out() { cerr << '\n'; }
template <typename T, typename... R> void debug_out(const T &f, const R &...r) {
  cerr << f << " ";
  debug_out(r...);
}
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]: ", debug_out(__VA_ARGS__);
inline ll read() {
  ll x = 0;
  int f = 0;
  char ch = getchar();
  while (ch < '0' || ch > '9')
    f |= (ch == '-'), ch = getchar();
  while (ch >= '0' && ch <= '9')
    x = (x << 3) + (x << 1) + ch - '0', ch = getchar();
  return x = f ? -x : x;
}
inline void write(ll x) {
  if (x == 0) {
    putchar('0');
    return;
  }
  if (x < 0) {
    putchar('-');
    x = -x;
  }
  static char s[23];
  int l = 0;
  while (x != 0)
    s[l++] = x % 10 + 48, x /= 10;
  while (l)
    putchar(s[--l]);
}
int lowbit(int x) { return x & (-x); }
template <class T> T big(const T &a1, const T &a2) { return a1 > a2 ? a1 : a2; }
template <typename T, typename... R> T big(const T &f, const R &...r) {
  return big(f, big(r...));
}
template <class T> T sml(const T &a1, const T &a2) { return a1 < a2 ? a1 : a2; }
template <typename T, typename... R> T sml(const T &f, const R &...r) {
  return sml(f, sml(r...));
}
template <class T, class U> inline void checkMin(T &x, U y) {
  if (y < x)
    x = y;
}
template <class T, class U> inline void checkMax(T &x, U y) {
  if (y > x)
    x = y;
}
template <class T, class U> inline bool ifMax(T &x, U y) {
  if (y > x)
    return x = y, true;
  return false;
}
template <class T, class U> inline bool ifMin(T &x, U y) {
  if (y < x)
    return x = y, true;
  return false;
}

const int M = 212345; // 2e5+5
const int inf = 0x3f3f3f3f;
const ll INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1000000007; // 1e9+7

// HAVE FREE OPEN IN MAIN FUNCTION

void init() {
  int a = read(), b = read();
  write(big(a + b, a * b, a - b));
  enter;
}

void solve() {}

int main() {
#ifndef ONLINE_JUDGE
  freopen("in.txt", "r", stdin);
  freopen("out.txt", "w", stdout);
#endif
  init();

  solve();

  return 0;
}

Fixed submission:
// #pragma GCC optimize("O3", "unroll-loops")
// #pragma GCC target("avx2")
#include <bits/stdc++.h>
#define FAST                                                                   \
  ios_base::sync_with_stdio(0);                                                \
  cin.tie(0);                                                                  \
  cout.tie(0)
#define FIXED cout << fixed << setprecision(12)
#define RANDOM srand(94385)
#define all(a) a.begin(), a.end()
#define shuffle(a)                                                             \
  for (int i = 0; i < sz(a); ++i)                                              \
    swap(a[i], a[rand() % sz(a)]);
#define enter puts("")
#define space putchar(' ')
#define Mem(a, x) memset(a, x, sizeof(a))
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

void debug_out() { cerr << '\n'; }
template <typename T, typename... R> void debug_out(const T &f, const R &...r) {
  cerr << f << " ";
  debug_out(r...);
}
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]: ", debug_out(__VA_ARGS__);
inline ll read() {
  ll x = 0;
  int f = 0;
  char ch = getchar();
  while (ch < '0' || ch > '9')
    f |= (ch == '-'), ch = getchar();
  while (ch >= '0' && ch <= '9')
    x = (x << 3) + (x << 1) + ch - '0', ch = getchar();
  return x = f ? -x : x;
}
inline void write(ll x) {
  if (x == 0) {
    putchar('0');
    return;
  }
  if (x < 0) {
    putchar('-');
    x = -x;
  }
  static char s[23];
  int l = 0;
  while (x != 0)
    s[l++] = x % 10 + 48, x /= 10;
  while (l)
    putchar(s[--l]);
}
int lowbit(int x) { return x & (-x); }
template <class T> T big(const T &a1, const T &a2) { return a1 > a2 ? a1 : a2; }
template <typename T, typename... R> T big(const T &f, const R &...r) {
  return big(f, big(r...));
}
template <class T> T sml(const T &a1, const T &a2) { return a1 < a2 ? a1 : a2; }
template <typename T, typename... R> T sml(const T &f, const R &...r) {
  return sml(f, sml(r...));
}
template <class T, class U> inline void checkMin(T &x, U y) {
  if (y < x)
    x = y;
}
template <class T, class U> inline void checkMax(T &x, U y) {
  if (y > x)
    x = y;
}
template <class T, class U> inline bool ifMax(T &x, U y) {
  if (y > x)
    return x = y, true;
  return false;
}
template <class T, class U> inline bool ifMin(T &x, U y) {
  if (y < x)
    return x = y, true;
  return false;
}

const int M = 212345; // 2e5+5
const int inf = 0x3f3f3f3f;
const ll INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1000000007; // 1e9+7

// HAVE FREE OPEN IN MAIN FUNCTION

void init() {
  int a = read(), b = read();
  write(big(a + b, a * b, a - b));
  enter;
}

void solve() {}

int main() {
  init();

  solve();

  return 0;
}