Language: C++

/*
* @Author: Kabid
* @Date:   2020-04-26 18:01:07
* @Last Modified by:   Kabid
* @Last Modified time: 2020-05-02 19:13:44
*/
#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<cstdlib>
#include<set>
#include<map>
#include<algorithm>
#define ll long long
#define  in(x) scanf("%d",&x);
#define out(x) printf("%d",x);
#define  ins(x)  scanf("%s",x);
#define outs(x) printf("%s",x);
#define lin puts("");
#define _ putchar(' ');
using namespace std;

int t;       //test cases
ll  n=0, k,m; //variables
long long w,x;
ll  a, b, d;
ll c;
ll p=100.0;
string s;
set<string>st;
ll i;
int main() {
	cin>>a>>b>>n;
	if(b==1){
		cout<<0;
	}
	else if(n<b){
		cout<<floor((a*n)/b)-a*floor(n/b);
	}
	else{
		m=0;
		for(i=1;b*i-1<=n;i++){
			w=b*i-1;
			m=max(m,floor((a*w)/b)-a*floor(w/b));

		}
		cout<<m;
	}
	

	return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:45:30: error: no matching function for call to 'max(long long int&, __gnu_cxx::__enable_if<true, double>::__type)'
   45 |                         m=max(m,floor((a*w)/b)-a*floor(w/b));
      |                           ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/string:51,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:7:
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:45:30: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and '__gnu_cxx::__enable_if<true, double>::__type' {aka 'double'})
   45 |                         m=max(m,floor((a*w)/b)-a*floor(w/b));
      |                           ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61,
                 from a.cc:14:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:45:30: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   45 |                         m=max(m,floor((a*w)/b)-a*floor(w/b));
      |                           ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~