Language: C++

#include<bits/stdc++.h>
using namespace std;
long long A[100][100];
main(){
    long long n;
    cin >> n;
    vector<pair<long long,long long> > v;
    for(long long i = 0; i < n; i++){
        long double a;
        cin >> a;
        long long x = (long long)(a * 1e9 + 1e-9);
        long long f = 0, t = 0;
        while( x %  2 == 0) x/=2, t++;
        while(x % 5 == 0) x /= 5, f++;
        v.push_back({f, t});

        A[f][t]++;
    }
    for(long long i = 60; i >= 0; i--){
        for(long long j = 60; j >= 0; j--){
            A[i][j] += A[i+1][j] + A[i][j+1] - A[i+1][j+1];
        }
    }
    long long ans = 0;
    for(auto x : v){
        long long a  = x.first-9, b = x.second-9;
        ans += A[max(0,-a+9)][max(0,-b+9)];
        if(a >= 0 && b >= 0) ans --;
    }
    cout<<ans/2<<endl;

}


Compiler output:
a.cc:4:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
    4 | main(){
      | ^~~~
a.cc: In function 'int main()':
a.cc:27:21: error: no matching function for call to 'max(int, long long int)'
   27 |         ans += A[max(0,-a+9)][max(0,-b+9)];
      |                  ~~~^~~~~~~~
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:27:21: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'long long int')
   27 |         ans += A[max(0,-a+9)][max(0,-b+9)];
      |                  ~~~^~~~~~~~
/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:27:21: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   27 |         ans += A[max(0,-a+9)][max(0,-b+9)];
      |                  ~~~^~~~~~~~
a.cc:27:34: error: no matching function for call to 'max(int, long long int)'
   27 |         ans += A[max(0,-a+9)][max(0,-b+9)];
      |                               ~~~^~~~~~~~
/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:27:34: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'long long int')
   27 |         ans += A[max(0,-a+9)][max(0,-b+9)];
      |                               ~~~^~~~~~~~
/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
/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:27:34: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   27 |         ans += A[max(0,-a+9)][max(0,-b+9)];
      |                               ~~~^~~~~~~~