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

#include "bits/stdc++.h"
// #include "ext/pb_ds/assoc_container.hpp"
// #include "ext/pb_ds/tree_policy.hpp"
// #define ordered_set tree<pair<int,int>, null_type,less<pair<int,int>>,
// rb_tree_tag,tree_order_statistics_node_update>
using namespace std;
// using namespace __gnu_pbds;
#define int long long int
#define pb push_back
#define vec vector<int>
#define fo(i, n) for (int i = 0; i < n; i++)
#define foo(i, a, b) for (int i = a; i < b; i++)
#define mp make_pair
#define deb(x) cout << #x << " --> " << x << endl;
#define deb1a(v)                                                               \\
  cout << #v << "--->" << endl;                                                \\
  for (auto it : v)                                                            \\
    cout << it << " ";                                                         \\
  cout << endl;
#define deb2a(v)                                                               \\
  cout << #v << "--->" << endl;                                                \\
  for (auto it : v) {                                                          \\
    for (auto it1 : it) {                                                      \\
      cout << it1 << " ";                                                      \\
    }                                                                          \\
    cout << endl;                                                              \\
  }
#define deb3a(v)                                                               \\
  cout << #v << "-->" << endl;                                                 \\
  for (auto it : v) {                                                          \\
    cout << it.fi << " " << it.se << endl;                                     \\
  }
#define mod 1000000007
#define so(v) sort(v.begin(), v.end())
#define fi first
#define se second
#define db1(x) cout << #x << "=" << x << '\\n'
#define db2(x, y) cout << #x << "=" << x << "," << #y << "=" << y << '\\n'
#define db3(x, y, z)                                                           \\
  cout << #x << "=" << x << "," << #y << "=" << y << "," << #z << "=" << z     \\
       << '\\n'
int power(int x, unsigned int y, int p) {
  int res = 1;
  x = x % p;
  while (y > 0) {
    if (y & 1)
      res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
int mI(int a, int m) { return power(a, m - 2, m); }
vector<int> v;

int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int a, b, n;
  cin >> a >> b >> n;
  int x = min(b - 1, n);
  int ans = (a * x) / b - a * (x / b);
  // fo(x,a+1){
  //     ans = max(ans, (a * x) / b - a * (x / b));
  // }
  cout << ans;
}


Error: TLE

Fixed submission:

#include "bits/stdc++.h"
// #include "ext/pb_ds/assoc_container.hpp"
// #include "ext/pb_ds/tree_policy.hpp"
// #define ordered_set tree<pair<int,int>, null_type,less<pair<int,int>>,
// rb_tree_tag,tree_order_statistics_node_update>
using namespace std;
// using namespace __gnu_pbds;
#define int long long int
#define pb push_back
#define vec vector<int>
#define fo(i, n) for (int i = 0; i < n; i++)
#define foo(i, a, b) for (int i = a; i < b; i++)
#define mp make_pair
#define deb(x) cout << #x << " --> " << x << endl;
#define deb1a(v)                                                               \\
  cout << #v << "--->" << endl;                                                \\
  for (auto it : v)                                                            \\
    cout << it << " ";                                                         \\
  cout << endl;
#define deb2a(v)                                                               \\
  cout << #v << "--->" << endl;                                                \\
  for (auto it : v) {                                                          \\
    for (auto it1 : it) {                                                      \\
      cout << it1 << " ";                                                      \\
    }                                                                          \\
    cout << endl;                                                              \\
  }
#define deb3a(v)                                                               \\
  cout << #v << "-->" << endl;                                                 \\
  for (auto it : v) {                                                          \\
    cout << it.fi << " " << it.se << endl;                                     \\
  }
#define mod 1000000007
#define so(v) sort(v.begin(), v.end())
#define fi first
#define se second
#define db1(x) cout << #x << "=" << x << '\\n'
#define db2(x, y) cout << #x << "=" << x << "," << #y << "=" << y << '\\n'
#define db3(x, y, z)                                                           \\
  cout << #x << "=" << x << "," << #y << "=" << y << "," << #z << "=" << z     \\
       << '\\n'
int power(int x, unsigned int y, int p) {
  int res = 1;
  x = x % p;
  while (y > 0) {
    if (y & 1)
      res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
int mI(int a, int m) { return power(a, m - 2, m); }
vector<int> v;

int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int a, b, n;
  cin >> a >> b >> n;
  int x = min(b, n);
  int ans = (a * x) / b - a * (x / b);
  fo(x, n + 1) { ans = max(ans, (a * x) / b - a * (x / b)); }
  cout << ans;
}