Language: C++

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

typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> pi;

#define F first
#define S second
#define PB push_back
#define MP make_pair
#define what_is(x) cerr << #x << " is " << x << endl;
#define MT make_tuple
#define eb emplace_back
#define rep(i, begin, end) for (__typeof(end) i = (begin) - ((begin) > (end)); i != (end) - ((begin) > (end)); i += 1 - 2 * ((begin) > (end)))

#define REP(i,a,b) for (int i = a; i <= b; i++)
#define FOR(i,n) for (int i=0;i < n ; i++)
#define error(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it, args); }

void err(istream_iterator<string> it) {}
template<typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
	cerr << *it << " = " << a << endl;
	err(++it, args...);
}



int func(ll a[], ll i, ll x){
	ll sum=0;
	if(i==1) return max(0,a[0]+a[1]-x);
	if(a[i] +a[i-1] <= x) return func(a,i-1,x);
	else if(a[i] > x) {
			sum+=a[i]-x;
			a[i]-=a[i]-x;
		}
	if(a[i] + a[i-1]> x ){
		sum+=a[i]+a[i-1]-x;
		a[i-1]-=a[i-1]+a[i]-x;
	} 
	return func(a,i-1,x)+sum;
}


int main(){
	ll n,x;
	cin >> n >> x;
	ll a[n];
	FOR(i,n) cin >> a[i];

	cout << func(a,n-1,x);

	return 0;
}

Compiler output:
a.cc: In function 'int func(ll*, ll, ll)':
a.cc:33:28: error: no matching function for call to 'max(int, ll)'
   33 |         if(i==1) return max(0,a[0]+a[1]-x);
      |                         ~~~^~~~~~~~~~~~~~~
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: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:33:28: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'll' {aka 'long long int'})
   33 |         if(i==1) return max(0,a[0]+a[1]-x);
      |                         ~~~^~~~~~~~~~~~~~~
/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 /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:2:
/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:33:28: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   33 |         if(i==1) return max(0,a[0]+a[1]-x);
      |                         ~~~^~~~~~~~~~~~~~~