Submission #1332766

#	Time	Username	Problem	Language	Result	Execution time	Memory
1332766		newbie_t	Amusement Park (CEOI19_amusementpark)	C++20	Compilation error	0 ms	0 KiB

amusementpark

#include <cstring>
#include <iostream>
using namespace std;
const int N = 18;
const int M = 998244353;
int a[N];
bool indepset[1 << N];
int popcount[1 << N];
int arg[1 << N];
int nodeid[1 << N];
long long f[1 << N];
int main() {
	int n, m;
	cin >> n >> m;
	for (int i = 1; i <= m; i++) {
		int u, v;
		cin >> u >> v;
		u--;
		v--;
		a[u] |= 1 << v;
		a[v] |= 1 << u;
	}
	for (int i = 0; i < n; i++) { nodeid[1 << i] = i; }
	for (int i = 0; i < (1 << n); i++) {
		popcount[i] = popcount[i >> 1] + (i & 1);
		arg[i] = (popcount[i] % 2) * 2 - 1;
	}
	indepset[0] = 1;
	for (int i = 1; i < (1 << n); i++) {
		if (indepset[i & (i - 1)] && (a[nodeid[i & (-i)]] & (i & (i - 1))) == 0) {
			indepset[i] = true;
		}
	}
	f[0] = 1;
	for (int i = 1; i < (1 << n); i++) {
		for (int j = i; j; j = (j - 1) & i) {
			if (indepset[j]) { f[i] = (f[i] + arg[j] * f[i ^ j]) % M; }
		}
	}
	f[(1 << n) - 1] = (f[(1 << n) - 1] + M) % M;
	cout << f[(1 << n) - 1] * m % M * ((M + 1) / 2) % M;
	return 0;
}

Compilation message (stderr)

amusementpark.cpp: In function 'int main()':
amusementpark.cpp:25:17: error: reference to 'popcount' is ambiguous
   25 |                 popcount[i] = popcount[i >> 1] + (i & 1);
      |                 ^~~~~~~~
In file included from /usr/include/c++/13/bits/stl_algobase.h:76,
                 from /usr/include/c++/13/string:51,
                 from /usr/include/c++/13/bits/locale_classes.h:40,
                 from /usr/include/c++/13/bits/ios_base.h:41,
                 from /usr/include/c++/13/ios:44,
                 from /usr/include/c++/13/ostream:40,
                 from /usr/include/c++/13/iostream:41,
                 from amusementpark.cpp:2:
/usr/include/c++/13/bit:426:5: note: candidates are: 'template<class _Tp> constexpr std::_If_is_unsigned_integer<_Tp, int> std::popcount(_Tp)'
  426 |     popcount(_Tp __x) noexcept
      |     ^~~~~~~~
amusementpark.cpp:8:5: note:                 'int popcount [262144]'
    8 | int popcount[1 << N];
      |     ^~~~~~~~
amusementpark.cpp:25:31: error: reference to 'popcount' is ambiguous
   25 |                 popcount[i] = popcount[i >> 1] + (i & 1);
      |                               ^~~~~~~~
/usr/include/c++/13/bit:426:5: note: candidates are: 'template<class _Tp> constexpr std::_If_is_unsigned_integer<_Tp, int> std::popcount(_Tp)'
  426 |     popcount(_Tp __x) noexcept
      |     ^~~~~~~~
amusementpark.cpp:8:5: note:                 'int popcount [262144]'
    8 | int popcount[1 << N];
      |     ^~~~~~~~
amusementpark.cpp:26:27: error: reference to 'popcount' is ambiguous
   26 |                 arg[i] = (popcount[i] % 2) * 2 - 1;
      |                           ^~~~~~~~
/usr/include/c++/13/bit:426:5: note: candidates are: 'template<class _Tp> constexpr std::_If_is_unsigned_integer<_Tp, int> std::popcount(_Tp)'
  426 |     popcount(_Tp __x) noexcept
      |     ^~~~~~~~
amusementpark.cpp:8:5: note:                 'int popcount [262144]'
    8 | int popcount[1 << N];
      |     ^~~~~~~~