answer.code:66:26: error: ‘std::pair<long long int, int> index [200009]’ redeclared as different kind of entity
   66 | pair<ll,int> index[200009];
      |                          ^
In file included from /usr/include/string.h:432,
                 from /usr/include/c++/13/cstring:42,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:121,
                 from answer.code:1:
/usr/include/strings.h:61:1: note: previous declaration ‘const char* index(const char*, int)’
   61 | index (const char *__s, int __c) __THROW
      | ^~~~~
answer.code: In function ‘int main()’:
answer.code:88:36: error: invalid types ‘<unresolved overloaded function type>[int]’ for array subscript
   88 |         for(int i=1;i<=n;++i) index[i]={s[i],i};
      |                                    ^
answer.code:89:19: error: invalid operands of types ‘<unresolved overloaded function type>’ and ‘int’ to binary ‘operator+’
   89 |         sort(index+1,index+n+1);
      |              ~~~~~^~
answer.code:89:27: error: invalid operands of types ‘<unresolved overloaded function type>’ and ‘int’ to binary ‘operator+’
   89 |         sort(index+1,index+n+1);
      |                      ~~~~~^~
answer.code:93:28: error: invalid types ‘<unresolved overloaded function type>[int]’ for array subscript
   93 |                 int p=index[i].second;
      |                            ^
answer.code:94:35: error: invalid types ‘<unresolved overloaded function type>[int]’ for array subscript
   94 |                 ans=(ans+1ll*index[i].first%mod*pow2(2,(i<k%n)+k/n)%mod)%mod;
      |                                   ^