/in/foo.cc:12:5: error: 'int index' redeclared as different kind of symbol
 int index;
     ^~~~~
In file included from /usr/include/c++/6/cstring:42:0,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:48,
                 from /in/foo.cc:1:
/usr/include/string.h:477:1: note: previous declaration 'const char* index(const char*, int)'
 index (const char *__s, int __c) __THROW
 ^~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:29:22: error: overloaded function with no contextual type information
         index = c[i].ma;
                      ^~
/in/foo.cc:30:26: error: invalid types 'node [60051][<unresolved overloaded function type>]' for array subscript
         (c[i].mi==a[index].ma)?arr[++l]=index:arr[--r]=index;
                          ^
/in/foo.cc:30:41: error: cannot resolve overloaded function 'index' based on conversion to type 'int'
         (c[i].mi==a[index].ma)?arr[++l]=index:arr[--r]=index;
                                         ^~~~~
/in/foo.cc:30:56: error: cannot resolve overloaded function 'index' based on conversion to type 'int'
         (c[i].mi==a[index].ma)?arr[++l]=index:arr[--r]=index;
                                                        ^~~~~