Language: C++

/*
--------------              |   /
      |                     |  /
      |                     | /
      |             *       |/          |    |         ------            *
      |                     |           |    |        /      \
      |             |       |\          |    |       |       |\          |
   \  |             |       | \         |    |       |       | \         |
    \ |             |       |  \        |    |        \     /   \        |
     V              |       |   \        \__/|         -----     \       |
*/
#include <bits/stdc++.h>
using namespace std;

#define EmiliaMyWife ios::sync_with_stdio(0); cin.tie(NULL);
#define mem(i,j) memset(i,j,sizeof (i));
#define F first
#define S second
#define lowbit(x) ((x)&(-(x)))
#define siz(v) (int)(v).size()
typedef int64_t ll;
typedef uint64_t ull;
typedef long double ld;
const double EPS  = 1e-8;
const int INF     = 0x3F3F3F3F;
const ll LINF     = 4611686018427387903;
const int MOD     = 1e9+7;
/*-----------------------------------------------------------------------------------------------------*/

const int N = 5e5+5;
int arr[N], cnt[N], vans[N];
int ans;
struct query {
	int i, l, r, b;
};
query que[N];

void add(int p) {
	cnt[arr[p]]++;
	if(cnt[arr[p]] == 1)
		ans++;
}
void rem(int p) {
	cnt[arr[p]]--;
	if(!cnt[arr[p]])
		ans--;
}

signed main() {
	EmiliaMyWife

	int n, q;
	cin >> n >> q;
	for(int i = 0; i < n; i++)
		cin >> arr[i];
	int w = sqrt(n)+1;
	for(int i = 0; i < q; i++)
		cin >> que[i].l >> que[i].r, que[i].l--, que[i].i = i, que[i].b = que[i].l/w;
	sort(que, que+q, [](query a, query b) {
		return (a.b==b.b?(a.r<b.r)^(b&1):a.b<b.b);
	});
	for(int i = 0, l = 0, r = 0; i < q; i++) {
		while(r < que[i].r)
			add(r++);
		while(l > que[i].l)
			add(--l);
		while(r > que[i].r)
			rem(--r);
		while(l < que[i].l)
			rem(l++);
		vans[que[i].i] = ans;
	}
	for(int i = 0; i < q; i++)
		cout << vans[i] << '\n';

	return 0;
}


Compiler output:
a.cc: In lambda function:
a.cc:60:46: error: no match for 'operator&' (operand types are 'query' and 'int')
   60 |                 return (a.b==b.b?(a.r<b.r)^(b&1):a.b<b.b);
      |                                             ~^~
      |                                             | |
      |                                             | int
      |                                             query
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:12:
/usr/include/c++/14/bitset:1557:5: note: candidate: 'template<long unsigned int _Nb> std::bitset<_Nb> std::operator&(const bitset<_Nb>&, const bitset<_Nb>&)'
 1557 |     operator&(const bitset<_Nb>& __x, const bitset<_Nb>& __y) _GLIBCXX_NOEXCEPT
      |     ^~~~~~~~
/usr/include/c++/14/bitset:1557:5: note:   template argument deduction/substitution failed:
a.cc:60:47: note:   'query' is not derived from 'const std::bitset<_Nb>'
   60 |                 return (a.b==b.b?(a.r<b.r)^(b&1):a.b<b.b);
      |                                               ^
In file included from /usr/include/c++/14/valarray:605,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:166:
/usr/include/c++/14/bits/valarray_after.h:411:5: note: candidate: 'template<class _Dom1, class _Dom2> std::_Expr<std::__detail::_BinClos<std::__bitwise_and, std::_Expr, std::_Expr, _Dom1, _Dom2>, typename std::__fun<std::__bitwise_and, typename _Dom1::value_type>::result_type> std::operator&(const _Expr<_Dom1, typename _Dom1::value_type>&, const _Expr<_Dom2, typename _Dom2::value_type>&)'
  411 |     _DEFINE_EXPR_BINARY_OPERATOR(&, struct std::__bitwise_and)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:411:5: note:   template argument deduction/substitution failed:
a.cc:60:47: note:   'query' is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   60 |                 return (a.b==b.b?(a.r<b.r)^(b&1):a.b<b.b);
      |                                               ^
/usr/include/c++/14/bits/valarray_after.h:411:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__bitwise_and, std::_Expr, std::_Constant, _Dom, typename _Dom::value_type>, typename std::__fun<std::__bitwise_and, typename _Dom1::value_type>::result_type> std::operator&(const _Expr<_Dom1, typename _Dom1::value_type>&, const typename _Dom::value_type&)'
  411 |     _DEFINE_EXPR_BINARY_OPERATOR(&, struct std::__bitwise_and)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:411:5: note:   template argument deduction/substitution failed:
a.cc:60:47: note:   'query' is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   60 |                 return (a.b==b.b?(a.r<b.r)^(b&1):a.b<b.b);
      |                                               ^
/usr/include/c++/14/bits/valarray_after.h:411:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__bitwise_and, std::_Constant, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__bitwise_and, typename _Dom1::value_type>::result_type> std::operator&(const typename _Dom::value_type&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  411 |     _DEFINE_EXPR_BINARY_OPERATOR(&, struct std::__bitwise_and)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:411:5: note:   template argument deduction/substitution failed:
a.cc:60:47: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'int'
   60 |                 return (a.b==b.b?(a.r<b.r)^(b&1):a.b<b.b);
      |                                               ^
/usr/include/c++/14/bits/valarray_after.h:411:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__bitwise_and, std::_Expr, std::_ValArray, _Dom, typename _Dom::value_type>, typename std::__fun<std::__bitwise_and, typename _Dom1::value_type>::result_type> std::operator&(const _Expr<_Dom1, typename _Dom1::value_type>&, const valarray<typename _Dom::value_type>&)'
  411 |     _DEFINE_EXPR_BINARY_OPERATOR(&, struct std::__bitwise_and)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:411:5: note:   template argument deduction/substitution failed:
a.cc:60:47: note:   'query' is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   60 |                 return (a.b==b.b?(a.r<b.r)^(b&1):a.b<b.b);
      |                                               ^
/usr/include/c++/14/bits/valarray_after.h:411:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__bitwise_and, std::_ValArray, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__bitwise_and, typename _Dom1::value_type>::result_type> std::operator&(const valarray<typename _Dom::value_type>&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  411 |     _DEFINE_EXPR_BINARY_OPERATOR(&, struct std::__bitwise_and)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:411:5: note:   template argument deduction/substitution failed:
a.cc:60:47: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'int'
   60 |                 return (a.b==b.b?(a.r<b.r)^(b&1):a.b<b.b);
      |                                               ^
/usr/include/c++/14/valarray:1202:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__bitwise_and, std::_ValArray, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__bitwise_and, _Tp>::result_type> std::operator&(const valarray<_Tp>&, const valarray<_Tp>&)'
 1202 | _DEFINE_BINARY_OPERATOR(&, __bitwise_and)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1202:1: note:   template argument deduction/substitution failed:
a.cc:60:47: note:   'query' is not derived from 'const std::valarray<_Tp>'
   60 |                 return (a.b==b.b?(a.r<b.r)^(b&1):a.b<b.b);
      |                                               ^
/usr/include/c++/14/valarray:1202:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__bitwise_and, std::_ValArray, std::_Constant, _Tp, _Tp>, typename std::__fun<std::__bitwise_and, _Tp>::result_type> std::operator&(const valarray<_Tp>&, const typename valarray<_Tp>::value_type&)'
 1202 | _DEFINE_BINARY_OPERATOR(&, __bitwise_and)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1202:1: note:   template argument deduction/substitution failed:
a.cc:60:47: note:   'query' is not derived from 'const std::valarray<_Tp>'
   60 |                 return (a.b==b.b?(a.r<b.r)^(b&1):a.b<b.b);
      |                                               ^
/usr/include/c++/14/valarray:1202:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__bitwise_and, std::_Constant, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__bitwise_and, _Tp>::result_type> std::operator&(const typename valarray<_Tp>::value_type&, const valarray<_Tp>&)'
 1202 | _DEFINE_BINARY_OPERATOR(&, __bitwise_and)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1202:1: note:   template argument deduction/substitution failed:
a.cc:60:47: note:   mismatched types 'const std::valarray<_Tp>' and 'int'
   60 |                 return (a.b==b.b?(a.r<b.r)^(b&1):a.b<b.b);
      |                                               ^
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:41:
/usr/include/c++/14/cstddef:141:3: note: candidate: 'constexpr std::byte std::operator&(byte, byte)'
  141 |   operator&(byte __l, byte __r) noexcept
      |   ^~~~~~~~
/usr/include/c++/14/cstddef:141:18: note:   no known conversion for argument 1 from 'query' to 'std::byte'
  141 |   operator&(byte __l, byte __r) noexcept
      |             ~~~~~^~~
In file included from /usr/include/c++/14/streambuf:43,
                 from /usr/include/c++/14/bits/streambuf_iterator.h:35,
                 from /usr/include/c++/14/iterator:66,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:54:
/usr/include/c++/14/bits/ios_base.h:84:3: note: candidate: 'constexpr std::_Ios_Fmtflags std::operator&(_Ios_Fmtflags, _Ios_Fmtflags)'
   84 |   operator&(_Ios_Fmtflags __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
      |   ^~~~~~~~
/usr/include/c++/14/bits/ios_base.h:84:27: note:   no known conversion for argument 1 from 'query' to 'std::_Ios_Fmtflags'
   84 |   operator&(_Ios_Fmtflags __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
      |             ~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/ios_base.h:134:3: note: candidate: 'constexpr std::_Ios_Openmode std::operator&(_Ios_Openmode, _Ios_Openmode)'
  134 |   operator&(_Ios_Openmode __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
      |   ^~~~~~~~
/usr/include/c++/14/bits/ios_base.h:134:27: note:   no known conversion for argument 1 from 'query' to 'std::_Ios_Openmode'
  134 |   operator&(_Ios_Openmode __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
      |             ~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/ios_base.h:181:3: note: candidate: 'constexpr std::_Ios_Iostate std::operator&(_Ios_Iostate, _Ios_Iostate)'
  181 |   operator&(_Ios_Iostate __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
      |   ^~~~~~~~
/usr/include/c++/14/bits/ios_base.h:181:26: note:   no known conversion for argument 1 from 'query' to 'std::_Ios_Iostate'
  181 |   operator&(_Ios_Iostate __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
      |             ~~~~~~~~~~~~~^~~
In file included from /usr/include/c++/14/bits/shared_ptr_atomic.h:33,
                 from /usr/include/c++/14/memory:81,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:56:
/usr/include/c++/14/bits/atomic_base.h:109:3: note: candidate: 'constexpr std::memory_order std::operator&(memory_order, __memory_order_modifier)'
  109 |   operator&(memory_order __m, __memory_order_modifier __mod) noexcept
      |   ^~~~~~~~
/usr/include/c++/14/bits/atomic_base.h:109:26: note:   no known conversion for argument 1 from 'query' to 'std::memory_order'
  109 |   operator&(memory_order __m, __memory_order_modifier __mod) noexcept
      |             ~~~~~~~~~~~~~^~~
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/st