Language: C++

#include<bits/stdc++.h>
using namespace std;
#define endl '\n'

string ans="";
int helper(string str1, int pt1, string str2, int pt2, vector<vector<int> > &dp)
    {
        if(pt1 == str1.length() || pt2==str2.length())
        {
            dp[pt1][pt2]= 0;
            return 0;
        }

        if(dp[pt1][pt2] != -1)
            return dp[pt1][pt2];

        int res;
        if(str1[pt1] == str2[pt2])
        {
           ans += str1[pt1];
            res= 1 +  helper(str1, pt1+1, str2 ,pt2+1, dp);
        }
        else
        {
            int first =helper(str1, pt1+1, str2, pt2, dp);
            int second =helper(str1, pt1, str2, pt2+1, dp);
            res =max(first, second);
        }
        dp[pt1][pt2]=res;
       return res;
    }

int longestCommonSubsequence(string str1, string str2)
    {
        int row=str1.length()+1;
        int col=str2.length()+1;

        vector<vector<int> > dp(row, vector<int> (col, -1));
        return helper(str1, 0, str2, 0, dp);
    }

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    string s1,s2;
    cin>s1>>s2;
    
     longestCommonSubsequence(s1, s2);
    //cout << lcsfulldp(s1, s2) <<endl;
     cout<<ans<<'\n';




    return 0;
}



Compiler output:
a.cc: In function 'int main()':
a.cc:48:11: error: no match for 'operator>>' (operand types are 'std::string' {aka 'std::__cxx11::basic_string<char>'} and 'std::string' {aka 'std::__cxx11::basic_string<char>'})
   48 |     cin>s1>>s2;
      |         ~~^~~~
      |         |   |
      |         |   basic_string<[...]>
      |         basic_string<[...]>
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:41,
                 from a.cc:1:
/usr/include/c++/14/cstddef:131:5: note: candidate: 'template<class _IntegerType> constexpr std::__byte_op_t<_IntegerType> std::operator>>(byte, _IntegerType)'
  131 |     operator>>(byte __b, _IntegerType __shift) noexcept
      |     ^~~~~~~~
/usr/include/c++/14/cstddef:131:5: note:   template argument deduction/substitution failed:
a.cc:48:9: note:   cannot convert 's1' (type 'std::string' {aka 'std::__cxx11::basic_string<char>'}) to type 'std::byte'
   48 |     cin>s1>>s2;
      |         ^~
In file included from /usr/include/c++/14/string:55,
                 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/basic_string.tcc:835:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
  835 |     operator>>(basic_istream<_CharT, _Traits>& __in,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.tcc:835:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
/usr/include/c++/14/bitset:1597:5: note: candidate: 'template<class _CharT, class _Traits, long unsigned int _Nb> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, bitset<_Nb>&)'
 1597 |     operator>>(std::basic_istream<_CharT, _Traits>& __is, bitset<_Nb>& __x)
      |     ^~~~~~~~
/usr/include/c++/14/bitset:1597:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
In file included from /usr/include/c++/14/istream:1109,
                 from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127:
/usr/include/c++/14/bits/istream.tcc:978:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, _CharT&)'
  978 |     operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c)
      |     ^~~~~~~~
/usr/include/c++/14/bits/istream.tcc:978:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
/usr/include/c++/14/istream:849:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(basic_istream<char, _Traits>&, unsigned char&)'
  849 |     operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c)
      |     ^~~~~~~~
/usr/include/c++/14/istream:849:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<char, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
/usr/include/c++/14/istream:854:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(basic_istream<char, _Traits>&, signed char&)'
  854 |     operator>>(basic_istream<char, _Traits>& __in, signed char& __c)
      |     ^~~~~~~~
/usr/include/c++/14/istream:854:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<char, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
/usr/include/c++/14/istream:896:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, _CharT*)'
  896 |     operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s)
      |     ^~~~~~~~
/usr/include/c++/14/istream:896:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
/usr/include/c++/14/istream:939:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(basic_istream<char, _Traits>&, unsigned char*)'
  939 |     operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s)
      |     ^~~~~~~~
/usr/include/c++/14/istream:939:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<char, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
/usr/include/c++/14/istream:945:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(basic_istream<char, _Traits>&, signed char*)'
  945 |     operator>>(basic_istream<char, _Traits>& __in, signed char* __s)
      |     ^~~~~~~~
/usr/include/c++/14/istream:945:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<char, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
/usr/include/c++/14/istream:1099:5: note: candidate: 'template<class _Istream, class _Tp> _Istream&& std::operator>>(_Istream&&, _Tp&&)'
 1099 |     operator>>(_Istream&& __is, _Tp&& __x)
      |     ^~~~~~~~
/usr/include/c++/14/istream:1099:5: note:   template argument deduction/substitution failed:
/usr/include/c++/14/istream: In substitution of 'template<class _Istream, class _Tp> _Istream&& std::operator>>(_Istream&&, _Tp&&) [with _Istream = std::__cxx11::basic_string<char>&; _Tp = std::__cxx11::basic_string<char>&]':
a.cc:48:13:   required from here
   48 |     cin>s1>>s2;
      |             ^~
/usr/include/c++/14/istream:1099:5: error: no type named 'type' in 'struct std::enable_if<false, void>'
 1099 |     operator>>(_Istream&& __is, _Tp&& __x)
      |     ^~~~~~~~
/usr/include/c++/14/complex:509:5: note: candidate: 'template<class _Tp, class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, complex<_Tp>&)'
  509 |     operator>>(basic_istream<_CharT, _Traits>& __is, complex<_Tp>& __x)
      |     ^~~~~~~~
/usr/include/c++/14/complex:509:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:143:
/usr/include/c++/14/iomanip:76:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, _Resetiosflags)'
   76 |     operator>>(basic_istream<_CharT, _Traits>& __is, _Resetiosflags __f)
      |     ^~~~~~~~
/usr/include/c++/14/iomanip:76:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
/usr/include/c++/14/iomanip:106:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, _Setiosflags)'
  106 |     operator>>(basic_istream<_CharT, _Traits>& __is, _Setiosflags __f)
      |     ^~~~~~~~
/usr/include/c++/14/iomanip:106:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
/usr/include/c++/14/iomanip:137:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, _Setbase)'
  137 |     operator>>(basic_istream<_CharT, _Traits>& __is, _Setbase __f)
      |     ^~~~~~~~
/usr/include/c++/14/iomanip:137:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
/usr/include/c++/14/iomanip:177:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, _Setfill<_CharT>)'
  177 |     operator>>(basic_istream<_CharT, _Traits>& __is, _Setfill<_CharT> __f)
      |     ^~~~~~~~
/usr/include/c++/14/iomanip:177:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
/usr/include/c++/14/iomanip:207:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(basic_istream<_CharT, _Traits>&, _Setprecision)'
  207 |     operator>>(basic_istream<_CharT, _Traits>& __is, _Setprecision __f)
      |     ^~~~~~~~
/usr/include/c++/14/iomanip:207:5: note:   template argument deduction/substitution failed:
a.cc:48:13: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
   48 |     cin>s1>>s2;
      |             ^~
/usr/include/