func_code_string: #include <bits/stdc++.h>   using namespace std;   template <typename _T>   inline void _DBG(const char *s, _T x) {     cerr << s <<   =   << x <<   n ;   }   template <typename _T, typename... args>   void _DBG(const char *s, _T x, args... a) {     while (*s !=  , ) cerr << *s++;     cerr <<   =   << x <<  , ;     _DBG(s + 1, a...);   }   vector<int> A;   vector<int> modded;   int main() {     int n;     cin >> n;     A.resize(n);     modded.resize(n);     for (int i = 0; i < n; i++) {       cin >> A[i];     }     int res = 0;     for (int i = 0; i < 27; i++) {       for (int j = 0; j < n; j++) {         modded[j] = A[j] % (1 << (i + 1));       }       sort((modded).begin(), (modded).end());       int l, r, cnt = 0;       for (int j = 0; j < n; j++) {         auto beg = modded.begin() + j + 1;         auto end = modded.end();         l = lower_bound(beg, end, (1 << i) - modded[j]) - modded.begin();         r = lower_bound(beg, end, (1 << (i + 1)) - modded[j]) - modded.begin();         cnt += (r - l);         l = lower_bound(beg, end, (1 << (i + 1)) + (1 << i) - modded[j]) -             modded.begin();         r = upper_bound(beg, end, (1 << (i + 2)) - 2 - modded[j]) -             modded.begin();         cnt += (r - l);       }       if (cnt & 1) {         res |= (1 << i);       }     }     cout << res <<   n ;     return 0;   }   