Language: C++

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

#pragma region typedef 
typedef long long ll;
typedef long double ld;
typedef pair<int, int> P;
#pragma endregion

#pragma region define
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define rep(i, n) for(int i = 0; (i) < (n); (i)++)
#define pb push_back
#define pf push_front
#pragma endregion

#pragma region const
const ld PI = 3.141592653589793;
#pragma endregion

#pragma region function
template<class T>bool chmax(T &a, const T &b){
  if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, T &b, T &c){
  if (b<a) { a=b; c++; return 1; } return 0; }
int sort_3int(int a, int b, int c){
  if (a>b) { swap(a,b); }
  if (a>c) { swap(a,c); }
  if (b>c) { swap(b,c); } return true;}
#pragma endregion

int main(){
  int n;
  cin >> n;
  vector<ll> a(n);
  rep(i, n) cin >> a[i];
  int ans = 0;

  for(int i = 1; i < n; i++){
    if (a[i-1] > a[i]){
      ans += max(a[i-1] - a[i], 0);
      a[i] = a[i-1];
    }
  }
  cout << ans << endl;

return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:43:17: error: no matching function for call to 'max(__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type, int)'
   43 |       ans += max(a[i-1] - a[i], 0);
      |              ~~~^~~~~~~~~~~~~~~~~~
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:2:
/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:43:17: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'int')
   43 |       ans += max(a[i-1] - a[i], 0);
      |              ~~~^~~~~~~~~~~~~~~~~~
/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:43:17: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   43 |       ans += max(a[i-1] - a[i], 0);
      |              ~~~^~~~~~~~~~~~~~~~~~