Language: C++

#include <bits/stdc++.h>
using #include <bits/stdc++.h>
using namespace std;
int dp[3001][3001];
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
   string a,b;
   cin>>a>>b;
   int i,j,k,l;
   for(i=1;i<a.size();i++)
   {
       for(j=1;j<b.size();j++)
       {
           if(a[i-1]==b[j-1])
           dp[i][j]=dp[i-1][j-1]+1;
           else
           dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
       }
   }
    k=a.size();
  l=b.size();
   string p="";
  while(k>0 && l>0)
  {
      if(a[k-1]==b[l-1])
      {
          p=p+a[k-1];
          k--;
          l--;
      }
      else
      {
          if(dp[k-1][l]>dp[k][l-1])
          {
              k--;
          }
          else
          l--;
      }
  }
 reverse(p.begin(),p.end());
 cout<<p;
}

Compiler output:
a.cc:2:7: error: stray '#' in program
    2 | using #include <bits/stdc++.h>
      |       ^
a.cc:2:8: error: expected nested-name-specifier before 'include'
    2 | using #include <bits/stdc++.h>
      |        ^~~~~~~
a.cc: In function 'int main()':
a.cc:7:5: error: 'ios_base' has not been declared
    7 |     ios_base::sync_with_stdio(false);
      |     ^~~~~~~~
a.cc:8:5: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    8 |     cin.tie(0);
      |     ^~~
      |     std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:146,
                 from a.cc:1:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:9:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    9 |     cout.tie(0);
      |     ^~~~
      |     std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:10:4: error: 'string' was not declared in this scope
   10 |    string a,b;
      |    ^~~~~~
a.cc:10:4: note: suggested alternatives:
In file included from /usr/include/c++/14/string:41,
                 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/stringfwd.h:77:33: note:   'std::string'
   77 |   typedef basic_string<char>    string;
      |                                 ^~~~~~
/usr/include/c++/14/string:76:11: note:   'std::pmr::string'
   76 |     using string    = basic_string<char>;
      |           ^~~~~~
a.cc:11:9: error: 'a' was not declared in this scope
   11 |    cin>>a>>b;
      |         ^
a.cc:11:12: error: 'b' was not declared in this scope
   11 |    cin>>a>>b;
      |            ^
a.cc:20:21: error: 'max' was not declared in this scope; did you mean 'std::max'?
   20 |            dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
      |                     ^~~
      |                     std::max
In file included from /usr/include/c++/14/algorithm:61,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: 'std::max' declared here
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
a.cc:25:10: error: expected ';' before 'p'
   25 |    string p="";
      |          ^~
      |          ;
a.cc:30:11: error: 'p' was not declared in this scope
   30 |           p=p+a[k-1];
      |           ^
a.cc:44:10: error: 'p' was not declared in this scope
   44 |  reverse(p.begin(),p.end());
      |          ^
a.cc:44:2: error: 'reverse' was not declared in this scope; did you mean 'std::reverse'?
   44 |  reverse(p.begin(),p.end());
      |  ^~~~~~~
      |  std::reverse
In file included from /usr/include/c++/14/algorithm:86:
/usr/include/c++/14/pstl/glue_algorithm_defs.h:249:1: note: 'std::reverse' declared here
  249 | reverse(_ExecutionPolicy&& __exec, _BidirectionalIterator __first, _BidirectionalIterator __last);
      | ^~~~~~~