Submission #742043

#	Time	Username	Problem	Language	Result	Execution time	Memory
742043		marvinthang	XOR Sum (info1cup17_xorsum)	C++17	100 / 100	1527 ms	13568 KiB

xorsum

/*************************************
*    author: marvinthang             *
*    created: 15.05.2023 19:40:24    *
*************************************/

#include <bits/stdc++.h>

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i--; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
    #include "debug.h"
#else
    #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
    #define DB(...) 23
    #define db(...) 23
    #define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }

// end of template

const int MAX = 1e6 + 6;
const int LOG = 30;

int N, A[MAX];

void init(void) {
    cin >> N;
    REP(i, N) cin >> A[i];
}

void process(void) {
    int res = 0;
    REPD(b, LOG) {
        sort(A, A + N);
        int j = N, k = N, l = N;
        REP(i, N) {
            j = max(j, i);
            k = max(k, i);
            l = max(l, i);
            while (j > i && A[j - 1] + A[i] >= MASK(b)) --j;
            while (k > i && A[k - 1] + A[i] >= MASK(b + 1)) --k;
            while (l > i && A[l - 1] + A[i] >= MASK(b + 1) + MASK(b)) --l;
            if (k - j + N - l & 1) res ^= MASK(b);
            int cnt = 0;
            FOR(j, i, N) if (BIT(A[i] + A[j], b)) ++cnt;
        }
        REP(i, N) A[i] &= ~MASK(b);
    }
    cout << res << '\n';
}

int main(void) {
    ios_base::sync_with_stdio(false); cin.tie(nullptr); // cout.tie(nullptr);
    file("test");
    init();
    process();
    cerr << "Time elapsed: " << TIME << " s.\n";
    return (0^0);
}

Compilation message (stderr)

xorsum.cpp: In function 'void process()':
xorsum.cpp:67:27: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   67 |             if (k - j + N - l & 1) res ^= MASK(b);
      |                 ~~~~~~~~~~^~~
xorsum.cpp: In function 'int main()':
xorsum.cpp:30:61: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
xorsum.cpp:78:5: note: in expansion of macro 'file'
   78 |     file("test");
      |     ^~~~
xorsum.cpp:30:94: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
xorsum.cpp:78:5: note: in expansion of macro 'file'
   78 |     file("test");
      |     ^~~~

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 21 / 21
• Subtask 4: 38 / 38
• Subtask 5: 23 / 23