Language: C++

#include<iostream>
#include<algorithm>
using namespace std;
const int inf = 0x7f7f7f7f;
const int MAXN = 1e6+1000;
const int MAXK = 1e6+1000;
inline int read() { //快读
	char ch = getchar();
	int x = 0, f = 1;
	while(ch < '0' || ch > '9') {
		if(ch == '-') f = -1;
		ch = getchar();
	}
	while('0' <= ch && ch <= '9') {
		x = x * 10 + ch - '0';
		ch = getchar();
	}
	return x * f;
}
inline int _max(int x1,int x2) { //取最大值
	return x1>x2 ? x1 : x2;
}
struct data {
	int L,R,ad; //左右边界及原位置（因为我们要离线排序后处理）
} a[MAXN];
int sum[MAXN],ans[MAXN],nxt[MAXN],head[MAXK],n,m,mx,num[MAXN];
inline int lowbit(int x) {
	return x&(-x); //树状数组lowbit
}
inline void add(int x,int v) {
	for(; x <= n; x+= lowbit(x)) {
		sum[x]+= v;
	}
	//树状数组更新操作
}
inline int _count(int x) {
	int tot = 0;
	for(; x; x-= lowbit(x)) {
		tot+= sum[x];
	}
	return tot;
	//树状数组查询操作
}
inline bool cmp(const data x1,const data x2) { //sort函数的cmp
	return x1.L==x2.L ? x1.R<x2.R : x1.L<x2.L;
}
void func() {
	n = read();m = read();
	for(int i = 1; i <= n; i++) {
		num[i] = read();
	}
	for(int i = n; i >= 1; i--) {
		nxt[i] = head[num[i]];
		head[num[i]] = i;
		mx = _max(mx,num[i]);
	}

	for(int i = 1; i <= m; i++) {
		a[i].L = read();
		a[i].R = read();
		a[i].ad = i; //存储初始位置
	}
	sort(a+1,a+m+1,cmp); //按R排序
	for(int i = 1; i <= mx; i++) {
		if(head[i]) {
			add(head[i],1); //打标记
		}
	}
	int now = 1;
	for(int i = 1; i <= m; i++) {
		while(now < a[i].L) {
			if(nxt[now]){
				add(nxt[now],1);
			}
			now++;
		}
		ans[a[i].ad] = _count(a[i].R)-_count(a[i].L-1); //按询问编号存储每组询问的结果
	}
	for(int i = 1; i <= m; i++){
		printf("%d\n",ans[i]);
	}
	return;
}
int main() {
	func();
	return 0;
}


Compiler output:
a.cc:44:23: error: reference to 'data' is ambiguous
   44 | inline bool cmp(const data x1,const data x2) { //sort函数的cmp
      |                       ^~~~
In file included from /usr/include/c++/14/string:53,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/range_access.h:344:5: note: candidates are: 'template<class _Tp> constexpr const _Tp* std::data(initializer_list<_Tp>)'
  344 |     data(initializer_list<_Tp> __il) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:334:5: note:                 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::data(_Tp (&)[_Nm])'
  334 |     data(_Tp (&__array)[_Nm]) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:323:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(const _Container&)'
  323 |     data(const _Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:312:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(_Container&)'
  312 |     data(_Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
a.cc:23:8: note:                 'struct data'
   23 | struct data {
      |        ^~~~
a.cc:44:37: error: reference to 'data' is ambiguous
   44 | inline bool cmp(const data x1,const data x2) { //sort函数的cmp
      |                                     ^~~~
/usr/include/c++/14/bits/range_access.h:344:5: note: candidates are: 'template<class _Tp> constexpr const _Tp* std::data(initializer_list<_Tp>)'
  344 |     data(initializer_list<_Tp> __il) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:334:5: note:                 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::data(_Tp (&)[_Nm])'
  334 |     data(_Tp (&__array)[_Nm]) noexcept
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:323:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(const _Container&)'
  323 |     data(const _Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
/usr/include/c++/14/bits/range_access.h:312:5: note:                 'template<class _Container> constexpr decltype (__cont.data()) std::data(_Container&)'
  312 |     data(_Container& __cont) noexcept(noexcept(__cont.data()))
      |     ^~~~
a.cc:23:8: note:                 'struct data'
   23 | struct data {
      |        ^~~~
a.cc: In function 'bool cmp(int, int)':
a.cc:45:19: error: request for member 'L' in 'x1', which is of non-class type 'const int'
   45 |         return x1.L==x2.L ? x1.R<x2.R : x1.L<x2.L;
      |                   ^
a.cc:45:25: error: request for member 'L' in 'x2', which is of non-class type 'const int'
   45 |         return x1.L==x2.L ? x1.R<x2.R : x1.L<x2.L;
      |                         ^
a.cc:45:32: error: request for member 'R' in 'x1', which is of non-class type 'const int'
   45 |         return x1.L==x2.L ? x1.R<x2.R : x1.L<x2.L;
      |                                ^
a.cc:45:37: error: request for member 'R' in 'x2', which is of non-class type 'const int'
   45 |         return x1.L==x2.L ? x1.R<x2.R : x1.L<x2.L;
      |                                     ^
a.cc:45:44: error: request for member 'L' in 'x1', which is of non-class type 'const int'
   45 |         return x1.L==x2.L ? x1.R<x2.R : x1.L<x2.L;
      |                                            ^
a.cc:45:49: error: request for member 'L' in 'x2', which is of non-class type 'const int'
   45 |         return x1.L==x2.L ? x1.R<x2.R : x1.L<x2.L;
      |                                                 ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:71,
                 from /usr/include/c++/14/string:51:
/usr/include/c++/14/bits/predefined_ops.h: In instantiation of 'constexpr bool __gnu_cxx::__ops::_Iter_comp_iter<_Compare>::operator()(_Iterator1, _Iterator2) [with _Iterator1 = data*; _Iterator2 = data*; _Compare = bool (*)(int, int)]':
/usr/include/c++/14/bits/stl_algo.h:1777:14:   required from 'void std::__insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = data*; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(int, int)>]'
 1777 |           if (__comp(__i, __first))
      |               ~~~~~~^~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1817:25:   required from 'void std::__final_insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = data*; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(int, int)>]'
 1817 |           std::__insertion_sort(__first, __first + int(_S_threshold), __comp);
      |           ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1908:31:   required from 'void std::__sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = data*; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(int, int)>]'
 1908 |           std::__final_insertion_sort(__first, __last, __comp);
      |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4805:18:   required from 'void std::sort(_RAIter, _RAIter, _Compare) [with _RAIter = data*; _Compare = bool (*)(int, int)]'
 4805 |       std::__sort(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp));
      |       ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:63:6:   required from here
   63 |         sort(a+1,a+m+1,cmp); //按R排序
      |         ~~~~^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/predefined_ops.h:158:30: error: cannot convert 'data' to 'int' in argument passing
  158 |         { return bool(_M_comp(*__it1, *__it2)); }
      |                       ~~~~~~~^~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/predefined_ops.h: In instantiation of 'bool __gnu_cxx::__ops::_Val_comp_iter<_Compare>::operator()(_Value&, _Iterator) [with _Value = data; _Iterator = data*; _Compare = bool (*)(int, int)]':
/usr/include/c++/14/bits/stl_algo.h:1757:20:   required from 'void std::__unguarded_linear_insert(_RandomAccessIterator, _Compare) [with _RandomAccessIterator = data*; _Compare = __gnu_cxx::__ops::_Val_comp_iter<bool (*)(int, int)>]'
 1757 |       while (__comp(__val, __next))
      |              ~~~~~~^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1785:36:   required from 'void std::__insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = data*; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(int, int)>]'
 1785 |             std::__unguarded_linear_insert(__i,
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
 1786 |                                 __gnu_cxx::__ops::__val_comp_iter(__comp));
      |                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1817:25:   required from 'void std::__final_insertion_sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = data*; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(int, int)>]'
 1817 |           std::__insertion_sort(__first, __first + int(_S_threshold), __comp);
      |           ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1908:31:   required from 'void std::__sort(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = data*; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(int, int)>]'
 1908 |           std::__final_insertion_sort(__first, __last, __comp);
      |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4805:18:   required from 'void std::sort(_RAIter, _RAIter, _Compare) [with _RAIter = data*; _Compare = bool (*)(int, int)]'
 4805 |       std::__sort(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp));
      |       ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:63:6:   required from here
   63 |         sort(a+1,a+m+1,cmp); //按R排序
      |         ~~~~^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/predefined_ops.h:240:30: error: cannot convert 'data' to 'int' in argument passing
  240 |         { return bool(_M_comp(__val, *__it)); }
      |                       ~~~~~~~^~~~~~~~~~~~~~
/usr/include/c++/14/bits/predefined_ops.h: In instantiation of 'bool __gnu_cxx::__ops::_Iter_comp_val<_Compare>::operator()(_Iterator, _Value&) [with _Iterator = data*; _Value = data; _Compare = bool (*)(int, int)]':
/usr/include/c++/14/bits/stl_heap.h:140:48:   required from 'void std::__push_heap(_RandomAccessIterator, _Distance, _Distance, _Tp, _Compare&) [with _RandomAccessIterator = data*; _Distance = long int; _Tp = data; _Compare = __gnu_cxx::__ops::_Iter_comp_val<bool (*)(int, int)>]'
  140 |       while (__holeIndex > __topIndex && __comp(__first + __parent, __value))
      |                                          ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_heap.h:247:23:   required from 'void std::__adjust_heap(_RandomAccessIterator, _Distance, _Distance, _Tp, _Compare) [with _RandomAccessIterator = data*; _Distance = long int; _Tp = data; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(int, int)>]'
  247 |       std::__push_heap(__first, __holeIndex, __topIndex,
      |       ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  248 |                        _GLIBCXX_MOVE(__value), __cmp);
      |                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_heap.h:356:22:   required from 'void std::__make_heap(_RandomAccessIterator, _RandomAccessIterator, _Compare&) [with _RandomAccessIterator = data*; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<bool (*)(int, int)>]'
  356 |           std::__adjust_heap(__first, __parent, __len, _GLIBCXX_MOVE(__value),
      |           ~~~~~~~~~~~~~~~~~~