Problem p02696 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
using namespace std;

// TYPEDEF
// ----------------------------------------
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> Pair;
typedef vector<ll> vll;
typedef vector<vector<ll>> Graph;
typedef vector<string> vs;
typedef vector<pair<ll, ll>> Pll;

// REPEAT
// ----------------------------------------
#define REP(i, n) for (ll i = 0; i < (ll)(n); i++)
#define REPD(i, n) for (ll i = n - 1; i >= 0; i--)
#define REPA(i, a)                                                             \\
  for (ll i = 0; i < (ll)(a.size()); i++)                                      \\
    ;
#define FOR(i, a, b) for (ll i = a; i <= (ll)(b); i++)
#define FORD(i, a, b) for (ll i = a; i >= (ll)(b); i--)
#define COUT(a) cout << (a) << endl;
#define ENDL(a) cout << endl;
#define COUTA(i, a)                                                            \\
  for (ll i = 0; i < (ll)(a.size()); i++) {                                    \\
    cout << (a)[i] << " ";                                                     \\
  }                                                                            \\
  cout << endl;

// UTIL
// ----------------------------------------
#define pb push_back
#define paired make_pair
#define ALL(a) (a).begin(), (a).end()
#define SORT(a) sort((a).begin(), (a).end())
#define RSORT(a) sort((a).rbegin(), (a).rend())

// DEBUG
// ----------------------------------------
#ifdef _DEBUG
#define debug(x) cout << "[debug] " << #x << ": " << x << endl
#else
#define debug(x)
#endif

template <typename T> void debugV(const vector<T> v) {
#ifdef _DEBUG
  rep(i, v.size()) { cout << i << ":" << v[i] << " "; }
  cout << endl;
#else
  (void)v;
#endif
}

// BIT FLAG
// ----------------------------------------
const unsigned int BIT_FLAG_0 = (1 << 0);   // 0000 0000 0000 0001
const unsigned int BIT_FLAG_1 = (1 << 1);   // 0000 0000 0000 0010
const unsigned int BIT_FLAG_2 = (1 << 2);   // 0000 0000 0000 0100
const unsigned int BIT_FLAG_3 = (1 << 3);   // 0000 0000 0000 1000
const unsigned int BIT_FLAG_4 = (1 << 4);   // 0000 0000 0001 0000
const unsigned int BIT_FLAG_5 = (1 << 5);   // 0000 0000 0010 0000
const unsigned int BIT_FLAG_6 = (1 << 6);   // 0000 0000 0100 0000
const unsigned int BIT_FLAG_7 = (1 << 7);   // 0000 0000 1000 0000
const unsigned int BIT_FLAG_8 = (1 << 8);   // 0000 0001 0000 0000
const unsigned int BIT_FLAG_9 = (1 << 9);   // 0000 0010 0000 0000
const unsigned int BIT_FLAG_10 = (1 << 10); // 0000 0100 0000 0000
const unsigned int BIT_FLAG_11 = (1 << 11); // 0000 1000 0000 0000

// CONST
// ----------------------------------------
constexpr ll INF = 0x3f3f3f3f3f3f3f3f;
constexpr double PI = 3.14159265358979323846; // or M_PI

void Main() {
  ll a, b, n, value;
  cin >> a >> b >> n;

  ll ans = 0;
  ll m = n;

  ll i;
  if (b <= n) {
    i = b - 1;
    value = floor(a * i / b) - a * floor(i / b);
    ans = max(ans, value);
  } else {
    i = n;
    value = floor(a * i / b) - a * floor(i / b);
    ans = max(ans, value);
  }

  // if (b < n) {
  //     m = n;
  // }

  // FOR(i, 1, m) {
  //     value = floor(a * i / b) - a * floor(i / b);
  //     ans = max(ans, value);
  // }

  COUT(ans);
}

int main() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
  cout << fixed << setprecision(15);
  Main();
}

/*

N M Q
3 4 3
1 3 3 100
1 2 2 10
2 3 2 10



*/


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
using namespace std;

// TYPEDEF
// ----------------------------------------
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> Pair;
typedef vector<ll> vll;
typedef vector<vector<ll>> Graph;
typedef vector<string> vs;
typedef vector<pair<ll, ll>> Pll;

// REPEAT
// ----------------------------------------
#define REP(i, n) for (ll i = 0; i < (ll)(n); i++)
#define REPD(i, n) for (ll i = n - 1; i >= 0; i--)
#define REPA(i, a)                                                             \\
  for (ll i = 0; i < (ll)(a.size()); i++)                                      \\
    ;
#define FOR(i, a, b) for (ll i = a; i <= (ll)(b); i++)
#define FORD(i, a, b) for (ll i = a; i >= (ll)(b); i--)
#define COUT(a) cout << (a) << endl;
#define ENDL(a) cout << endl;
#define COUTA(i, a)                                                            \\
  for (ll i = 0; i < (ll)(a.size()); i++) {                                    \\
    cout << (a)[i] << " ";                                                     \\
  }                                                                            \\
  cout << endl;

// UTIL
// ----------------------------------------
#define pb push_back
#define paired make_pair
#define ALL(a) (a).begin(), (a).end()
#define SORT(a) sort((a).begin(), (a).end())
#define RSORT(a) sort((a).rbegin(), (a).rend())

// DEBUG
// ----------------------------------------
#ifdef _DEBUG
#define debug(x) cout << "[debug] " << #x << ": " << x << endl
#else
#define debug(x)
#endif

template <typename T> void debugV(const vector<T> v) {
#ifdef _DEBUG
  rep(i, v.size()) { cout << i << ":" << v[i] << " "; }
  cout << endl;
#else
  (void)v;
#endif
}

// BIT FLAG
// ----------------------------------------
const unsigned int BIT_FLAG_0 = (1 << 0);   // 0000 0000 0000 0001
const unsigned int BIT_FLAG_1 = (1 << 1);   // 0000 0000 0000 0010
const unsigned int BIT_FLAG_2 = (1 << 2);   // 0000 0000 0000 0100
const unsigned int BIT_FLAG_3 = (1 << 3);   // 0000 0000 0000 1000
const unsigned int BIT_FLAG_4 = (1 << 4);   // 0000 0000 0001 0000
const unsigned int BIT_FLAG_5 = (1 << 5);   // 0000 0000 0010 0000
const unsigned int BIT_FLAG_6 = (1 << 6);   // 0000 0000 0100 0000
const unsigned int BIT_FLAG_7 = (1 << 7);   // 0000 0000 1000 0000
const unsigned int BIT_FLAG_8 = (1 << 8);   // 0000 0001 0000 0000
const unsigned int BIT_FLAG_9 = (1 << 9);   // 0000 0010 0000 0000
const unsigned int BIT_FLAG_10 = (1 << 10); // 0000 0100 0000 0000
const unsigned int BIT_FLAG_11 = (1 << 11); // 0000 1000 0000 0000

// CONST
// ----------------------------------------
constexpr ll INF = 0x3f3f3f3f3f3f3f3f;
constexpr double PI = 3.14159265358979323846; // or M_PI

void Main() {
  ll a, b, n, value;
  cin >> a >> b >> n;

  ll ans = 0;
  FOR(i, 1, (b < n) ? b : n) {
    value = floor(a * i / b) - a * floor(i / b);
    ans = max(ans, value);
    // COUT(i);
    // COUT(ans);
    // cout << endl;
  }

  COUT(ans);
}

int main() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
  cout << fixed << setprecision(15);
  Main();
}

/*

N M Q
3 4 3
1 3 3 100
1 2 2 10
2 3 2 10



*/