Language: C++

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

#define rep(i, a) for (int i = 0; (i) < (int) (a); (i)++)
#define reps(i, a, b) for (int i = (int) (a); (i) < (int) (b); (i)++)
#define rrep(i, a) for (int i = (int) a-1; (i) >= 0; (i)--)
#define rreps(i, a, b) for (int i = (int) (a)-1; (i) >= (int) (b); (i)--)
#define MP(a, b) make_pair((a), (b))
#define PB(a) push_back((a))
#define all(v) (v).begin(), (v).end()
#define PERM(v) next_permutation(all(v))
#define UNIQUE(v) sort(all(v));(v).erase(unique(all(v)), v.end())
#define CIN(type, x) type x;cin >> x
#define TRUE__  "Yes"
#define FALSE__ "No"
#define PRINT(f) if((f)){cout << (TRUE__) << endl;}else{cout << FALSE__ << endl;}
#define RS(N) resize(N)
#define CINV(v, N) do {\
	v.RS(N);\
	rep(i, N) cin >> v[i];\
} while (0);
#define RCINV(v, N) do {\
	v.RS(N);\
	rrep(i, N) cin >> v[i];\
} while (0);

#define MOD 1000000007

void init();
void solve();

signed main()
{
	init();
	solve();
}

ll n, m, d;

void init()
{
	cin >> n >> m >> d;
}

void print(double x)
{
	cout << fixed << setprecision(12) << x * (m - 1) << endl;
}

void solve()
{
	if (d == 0) {
		double res = (double) 1 / n;
		print(res);
		return;
	}
	double res = 0;
	res += max(0, n - d) * 2;
	res /= n * n;
	print(res);
}


Compiler output:
a.cc: In function 'void solve()':
a.cc:60:19: error: no matching function for call to 'max(int, ll)'
   60 |         res += max(0, n - d) * 2;
      |                ~~~^~~~~~~~~~
In file included from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/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:60:19: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'll' {aka 'long long int'})
   60 |         res += max(0, n - d) * 2;
      |                ~~~^~~~~~~~~~
/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:
/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:60:19: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   60 |         res += max(0, n - d) * 2;
      |                ~~~^~~~~~~~~~