Language: C++

#include <bits/stdc++.h>
using namespace std;
#define ll long long 
#define p_b push_back
#define pl pair<ll,ll>

ll MOD = 1000000007;
// ll fact[2000005];
// ll modexpo(ll a,ll b)
// {
// 	if(b==0)
// 	{
// 		return 1;

// 	}
// 	if(b==1)
// 	{
// 		return a%MOD;
// 	}
// 	else
// 	{
// 		ll temp = modexpo(a,b/2);
// 		temp = temp*temp;
// 		temp%= MOD;
// 		if(b%2==1)
// 		{
// 			temp = (temp*a);
// 			temp %= MOD;
// 		}
// 		return temp;
// 	}
// }

// ll modinv(ll x)
// {
// 	return modexpo(x,MOD - 2);
// }
// ll nCr(ll n,ll r)
// {
// 	ll temp = fact[n] * (modinv (fact[r]));
// 	temp %= MOD;
// 	temp *= (modinv(fact[n-r]));
// 	temp %= MOD;
// 	return temp;
// }
ll val[3005];
ll wt[3005];
map<ll,ll> dp[3005][3005];
ll n;
ll recurse(ll idx,ll left)
{
	if(dp[idx][left] != -1)
	{
		return dp[idx][left];
	}
	ll temp = 0;
	if(idx == n)
	{
		return dp[idx][left] = 0;
	}
	if(left >0)
	 temp = recurse(idx+1,left-wt[idx])+val[idx];
	
	temp = max(temp,recurse(idx+1,left));
	return dp[idx][left] = temp;
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	int t;
	t= 1;


	// ll i;
	// fact[0] = 1;
	// for(i=1;i<2000005;i++)
	// {
	// 	fact[i] = i*(fact[i-1]);
	// 	fact[i] %= MOD;

	// }
	

	//cin >> t;
	while(t--)
	{
		ll ti;
		cin >> n >> ti;
		ll i;
		ll j;
		for(i=0;i<3005;i++)
		{
			for(j=0;j<3005;j++)
			{
				dp[i][j] = -1;

			}
		}

		for(i=0;i<n;i++)
		{
			cin >> wt[i] >> val[i] ;
		}
		cout << recurse(0,ti) << endl;

	}
	return 0;
}

Compiler output:
a.cc: In function 'long long int recurse(long long int, long long int)':
a.cc:52:26: error: no match for 'operator!=' (operand types are 'std::map<long long int, long long int>' and 'int')
   52 |         if(dp[idx][left] != -1)
      |            ~~~~~~~~~~~~~ ^~ ~~
      |                        |    |
      |                        |    int
      |                        std::map<long long int, long long int>
In file included from /usr/include/c++/14/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:181,
                 from a.cc:1:
/usr/include/c++/14/bits/regex.h:1132:5: note: candidate: 'template<class _BiIter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const sub_match<_BiIter>&)'
 1132 |     operator!=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1132:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   'std::map<long long int, long long int>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   52 |         if(dp[idx][left] != -1)
      |                              ^
/usr/include/c++/14/bits/regex.h:1212:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator!=(__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&, const sub_match<_BiIter>&)'
 1212 |     operator!=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1212:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   'std::map<long long int, long long int>' is not derived from 'std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>'
   52 |         if(dp[idx][left] != -1)
      |                              ^
/usr/include/c++/14/bits/regex.h:1305:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&)'
 1305 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1305:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   'std::map<long long int, long long int>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   52 |         if(dp[idx][left] != -1)
      |                              ^
/usr/include/c++/14/bits/regex.h:1379:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)'
 1379 |     operator!=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1379:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   52 |         if(dp[idx][left] != -1)
      |                              ^
/usr/include/c++/14/bits/regex.h:1473:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)'
 1473 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1473:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   'std::map<long long int, long long int>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   52 |         if(dp[idx][left] != -1)
      |                              ^
/usr/include/c++/14/bits/regex.h:1547:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)'
 1547 |     operator!=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1547:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   52 |         if(dp[idx][left] != -1)
      |                              ^
/usr/include/c++/14/bits/regex.h:1647:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)'
 1647 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1647:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   'std::map<long long int, long long int>' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   52 |         if(dp[idx][left] != -1)
      |                              ^
/usr/include/c++/14/bits/regex.h:2213:5: note: candidate: 'template<class _Bi_iter, class _Alloc> bool std::__cxx11::operator!=(const match_results<_BiIter, _Alloc>&, const match_results<_BiIter, _Alloc>&)'
 2213 |     operator!=(const match_results<_Bi_iter, _Alloc>& __m1,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:2213:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   'std::map<long long int, long long int>' is not derived from 'const std::__cxx11::match_results<_BiIter, _Alloc>'
   52 |         if(dp[idx][left] != -1)
      |                              ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/bits/stl_pair.h:1052:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator!=(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1052 |     operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1052:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   'std::map<long long int, long long int>' is not derived from 'const std::pair<_T1, _T2>'
   52 |         if(dp[idx][left] != -1)
      |                              ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:67:
/usr/include/c++/14/bits/stl_iterator.h:455:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator!=(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  455 |     operator!=(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:455:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   'std::map<long long int, long long int>' is not derived from 'const std::reverse_iterator<_Iterator>'
   52 |         if(dp[idx][left] != -1)
      |                              ^
/usr/include/c++/14/bits/stl_iterator.h:500:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator!=(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  500 |     operator!=(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:500:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   'std::map<long long int, long long int>' is not derived from 'const std::reverse_iterator<_Iterator>'
   52 |         if(dp[idx][left] != -1)
      |                              ^
/usr/include/c++/14/bits/stl_iterator.h:1686:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator!=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1686 |     operator!=(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1686:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   'std::map<long long int, long long int>' is not derived from 'const std::move_iterator<_IteratorL>'
   52 |         if(dp[idx][left] != -1)
      |                              ^
/usr/include/c++/14/bits/stl_iterator.h:1753:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator!=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1753 |     operator!=(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1753:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   'std::map<long long int, long long int>' is not derived from 'const std::move_iterator<_IteratorL>'
   52 |         if(dp[idx][left] != -1)
      |                              ^
In file included from /usr/include/c++/14/bits/char_traits.h:42,
                 from /usr/include/c++/14/string:42,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/bits/postypes.h:197:5: note: candidate: 'template<class _StateT> bool std::operator!=(const fpos<_StateT>&, const fpos<_StateT>&)'
  197 |     operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/postypes.h:197:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   'std::map<long long int, long long int>' is not derived from 'const std::fpos<_StateT>'
   52 |         if(dp[idx][left] != -1)
      |                              ^
In file included from /usr/include/c++/14/string:43:
/usr/include/c++/14/bits/allocator.h:243:5: note: candidate: 'template<class _T1, class _T2> bool std::operator!=(const allocator<_CharT>&, const allocator<_T2>&)'
  243 |     operator!=(const allocator<_T1>&, const allocator<_T2>&)
      |     ^~~~~~~~
/usr/include/c++/14/bits/allocator.h:243:5: note:   template argument deduction/substitution failed:
a.cc:52:30: note:   'std::map<long long int, long long int>' is not derived from 'const std::allocator<_CharT>'
   52 |         if(dp[idx][left] != -1)
      |                              ^
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54:
/usr/include/c++/14/string_view:651:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator!=(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  651 |     operator!=(basi