foo.cc: In function ‘bool cmp(stu, stu)’:
foo.cc:8:33: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
    8 |         return x.s>y.s||x.s==y.s&&x.xh<y.xh;
      |                         ~~~~~~~~^~~~~~~~~~~
foo.cc: In function ‘int main()’:
foo.cc:29:45: error: cannot convert ‘stu’ to ‘int’ in assignment
   29 |                                 win[i]=a[2*i];
      |                                        ~~~~~^
      |                                             |
      |                                             stu
foo.cc:30:48: error: cannot convert ‘stu’ to ‘int’ in assignment
   30 |                                 lose[i]=a[2*i-1];
      |                                         ~~~~~~~^
      |                                                |
      |                                                stu
foo.cc:35:45: error: cannot convert ‘stu’ to ‘int’ in assignment
   35 |                                 win[i]=a[2*i];
      |                                        ~~~~~^
      |                                             |
      |                                             stu
foo.cc:36:48: error: cannot convert ‘stu’ to ‘int’ in assignment
   36 |                                 lose[i]=a[i*2-1];
      |                                         ~~~~~~~^
      |                                                |
      |                                                stu
foo.cc:39:22: error: no matching function for call to ‘merge(int*, int*, int*, stu*, bool (&)(stu, stu))’
   39 |                 merge(lose+1,lose+1+n,win+1+n,a+1,cmp);
      |                 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/algorithm:61,
                 from stdc++.h:51:
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_algo.h:4857:5: note: candidate: ‘template<class _IIter1, class _IIter2, class _OIter> _OIter std::merge(_IIter1, _IIter1, _IIter2, _IIter2, _OIter)’
 4857 |     merge(_InputIterator1 __first1, _InputIterator1 __last1,
      |     ^~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_algo.h:4857:5: note:   template argument deduction/substitution failed:
foo.cc:39:22: note:   deduced conflicting types for parameter ‘_IIter2’ (‘int*’ and ‘stu*’)
   39 |                 merge(lose+1,lose+1+n,win+1+n,a+1,cmp);
      |                 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_algo.h:4908:5: note: candidate: ‘template<class _IIter1, class _IIter2, class _OIter, class _Compare> _OIter std::merge(_IIter1, _IIter1, _IIter2, _IIter2, _OIter, _Compare)’
 4908 |     merge(_InputIterator1 __first1, _InputIterator1 __last1,
      |     ^~~~~
/nix/gcc-14.2.1.20250322/include/c++/14.2.1.20250322/bits/stl_algo.h:4908:5: note:   candidate expects 6 arguments, 5 provided