Language: C++

http://drken1215.hatenablog.com/entry/2019/02/03/224200
#include <iostream>
#include <vector>
using namespace std;

int main() {
    int N;
    long long K;
    cin >> N >> K;
    vector<long long> A(N);
    for (int i = 0; i < N; ++i) cin >> A[i];
        
    long long res = 0;
    for (int d = 60; d >= -1; --d) { // d = -1 は X = K の場合//どこをdにするかを全探索
        if (d != -1 && !(K & (1LL<<d))) continue;//XとKのd桁目が一致
        
        long long tmp = 0;
        for (int e = 60; e >= 0; --e) {//各桁の排他的論理和を足し上げる
            long long mask = 1LL<<e;
            int num = 0;
            for (int i = 0; i < N; ++i) if (A[i] & mask) ++num;//e桁目に立っているbitの本数を数えている
            
            if (e > d) {
                if (K & mask) tmp += mask * (N - num);//Kのe桁目が立っているなら、Xのe桁目も立てる　だからAで立っていない分が排他的論理和を取った後に残る
                else tmp += mask * num;//Kのe桁目が立っていないとき
            }
            else if (e == d) {//Xのe桁目は0
                tmp += mask * num;//Aで立っているe桁目のbitは全部排他的論理和を取った後もたっている
            }
            else {
                tmp += mask * max(num, N - num);//Xのe桁目を立てるか立てないかはmaxを取って決める
            }
        }
        res = max(res, tmp);
    }
    cout << res << endl;
}

Compiler output:
a.cc:1:1: error: 'http' does not name a type
    1 | http://drken1215.hatenablog.com/entry/2019/02/03/224200
      | ^~~~
In file included from /usr/include/c++/14/iosfwd:42,
                 from /usr/include/c++/14/ios:40,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:2:
/usr/include/c++/14/bits/postypes.h:68:11: error: 'ptrdiff_t' does not name a type
   68 |   typedef ptrdiff_t     streamsize; // Signed integral type
      |           ^~~~~~~~~
/usr/include/c++/14/bits/postypes.h:41:1: note: 'ptrdiff_t' is defined in header '<cstddef>'; this is probably fixable by adding '#include <cstddef>'
   40 | #include <cwchar> // For mbstate_t
  +++ |+#include <cstddef>
   41 | 
In file included from /usr/include/c++/14/bits/exception_ptr.h:38,
                 from /usr/include/c++/14/exception:166,
                 from /usr/include/c++/14/ios:41:
/usr/include/c++/14/new:131:26: error: declaration of 'operator new' as non-function
  131 | _GLIBCXX_NODISCARD void* operator new(std::size_t) _GLIBCXX_THROW (std::bad_alloc)
      |                          ^~~~~~~~
/usr/include/c++/14/new:131:44: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  131 | _GLIBCXX_NODISCARD void* operator new(std::size_t) _GLIBCXX_THROW (std::bad_alloc)
      |                                            ^~~~~~
In file included from /usr/include/wchar.h:35,
                 from /usr/include/c++/14/cwchar:44,
                 from /usr/include/c++/14/bits/postypes.h:40:
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:132:41: error: attributes after parenthesized initializer ignored [-fpermissive]
  132 |   __attribute__((__externally_visible__));
      |                                         ^
/usr/include/c++/14/new:133:26: error: declaration of 'operator new []' as non-function
  133 | _GLIBCXX_NODISCARD void* operator new[](std::size_t) _GLIBCXX_THROW (std::bad_alloc)
      |                          ^~~~~~~~
/usr/include/c++/14/new:133:46: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  133 | _GLIBCXX_NODISCARD void* operator new[](std::size_t) _GLIBCXX_THROW (std::bad_alloc)
      |                                              ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:134:41: error: attributes after parenthesized initializer ignored [-fpermissive]
  134 |   __attribute__((__externally_visible__));
      |                                         ^
/usr/include/c++/14/new:140:29: error: 'std::size_t' has not been declared
  140 | void operator delete(void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
      |                             ^~~
/usr/include/c++/14/new:142:31: error: 'std::size_t' has not been declared
  142 | void operator delete[](void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
      |                               ^~~
/usr/include/c++/14/new:145:26: error: declaration of 'operator new' as non-function
  145 | _GLIBCXX_NODISCARD void* operator new(std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
      |                          ^~~~~~~~
/usr/include/c++/14/new:145:44: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  145 | _GLIBCXX_NODISCARD void* operator new(std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
      |                                            ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:145:52: error: expected primary-expression before 'const'
  145 | _GLIBCXX_NODISCARD void* operator new(std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
      |                                                    ^~~~~
/usr/include/c++/14/new:147:26: error: declaration of 'operator new []' as non-function
  147 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
      |                          ^~~~~~~~
/usr/include/c++/14/new:147:46: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  147 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
      |                                              ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:147:54: error: expected primary-expression before 'const'
  147 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
      |                                                      ^~~~~
/usr/include/c++/14/new:154:26: error: declaration of 'operator new' as non-function
  154 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t)
      |                          ^~~~~~~~
/usr/include/c++/14/new:154:44: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  154 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t)
      |                                            ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:154:68: error: expected primary-expression before ')' token
  154 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t)
      |                                                                    ^
/usr/include/c++/14/new:155:73: error: attributes after parenthesized initializer ignored [-fpermissive]
  155 |   __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
      |                                                                         ^
/usr/include/c++/14/new:156:26: error: declaration of 'operator new' as non-function
  156 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t, const std::nothrow_t&)
      |                          ^~~~~~~~
/usr/include/c++/14/new:156:44: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  156 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t, const std::nothrow_t&)
      |                                            ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:156:68: error: expected primary-expression before ',' token
  156 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t, const std::nothrow_t&)
      |                                                                    ^
/usr/include/c++/14/new:156:70: error: expected primary-expression before 'const'
  156 | _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t, const std::nothrow_t&)
      |                                                                      ^~~~~
/usr/include/c++/14/new:162:26: error: declaration of 'operator new []' as non-function
  162 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t)
      |                          ^~~~~~~~
/usr/include/c++/14/new:162:46: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  162 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t)
      |                                              ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:162:70: error: expected primary-expression before ')' token
  162 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t)
      |                                                                      ^
/usr/include/c++/14/new:163:73: error: attributes after parenthesized initializer ignored [-fpermissive]
  163 |   __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
      |                                                                         ^
/usr/include/c++/14/new:164:26: error: declaration of 'operator new []' as non-function
  164 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t, const std::nothrow_t&)
      |                          ^~~~~~~~
/usr/include/c++/14/new:164:46: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  164 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t, const std::nothrow_t&)
      |                                              ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/new:164:70: error: expected primary-expression before ',' token
  164 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t, const std::nothrow_t&)
      |                                                                      ^
/usr/include/c++/14/new:164:72: error: expected primary-expression before 'const'
  164 | _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t, const std::nothrow_t&)
      |                                                                        ^~~~~
/usr/include/c++/14/new:171:29: error: 'std::size_t' has not been declared
  171 | void operator delete(void*, std::size_t, std::align_val_t)
      |                             ^~~
/usr/include/c++/14/new:173:31: error: 'std::size_t' has not been declared
  173 | void operator delete[](void*, std::size_t, std::align_val_t)
      |                               ^~~
/usr/include/c++/14/new:179:33: error: declaration of 'operator new' as non-function
  179 | _GLIBCXX_NODISCARD inline void* operator new(std::size_t, void* __p) _GLIBCXX_USE_NOEXCEPT
      |                                 ^~~~~~~~
/usr/include/c++/14/new:179:51: error: 'size_t' is not a member of 'std'; did you