Language: C++

#include <iostream>
#include <algorithm>
#include <map>
#include <vector>
#include <cstring>
using namespace std;
typedef long long ll;
const int N=1e6+20;
const int M=30;
char s[M][M]={{"dream"},{"dreamer"},{"erase"},{"eraser"}};
int len[5];

int root,num=0;
int next[N][M],end[N];//trie next[u][id] u结点编号 
void insert(int x)
{
	int u=0,l=len[x];
	for(int i=0;i<l;i++)
	{
		char t=s[x][i];
		int id=t-'a';
		if(!next[u][id])
		{
			next[u][id]=++num;
		}
		u=next[u][id];	
	}
	end[u]=x;//单词结束标记 

}
char str[N],n;
bool flag=false;
void dfs(int pos)
{
	if(pos==n)
	{
		flag=true;
		return;
	}
	if(!flag)
	{
		int u=root;
		for(int i=pos+1;i<=n;i++)
		{
			int id=str[i]-'a';
			u=next[u][id];
			
			if(!u)
			break;
		
			if(end[u]!=-1)
			{
				dfs(pos+len[end[u]]);//
			}
		}
		
	}
}
int main()
{
	memset(next,0,sizeof(next));
	memset(end,-1,sizeof(end));
	root=0;
	scanf("%s",str+1);	
	n=strlen(str+1);
	for(int i=0;i<4;i++)//dictionary
	{
		len[i]=strlen(s[i]);
		insert(i);
	}
	dfs(0);//暴力匹配 
	if(flag)
	cout<<"YES"<<endl;
	else
	cout<<"NO"<<endl;
	return 0;
} 

Compiler output:
a.cc: In function 'void insert(int)':
a.cc:22:21: error: reference to 'next' is ambiguous
   22 |                 if(!next[u][id])
      |                     ^~~~
In file included from /usr/include/c++/14/string:47,
                 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/stl_iterator_base_funcs.h:232:5: note: candidates are: 'template<class _InputIterator> constexpr _InputIterator std::next(_InputIterator, typename iterator_traits<_Iter>::difference_type)'
  232 |     next(_InputIterator __x, typename
      |     ^~~~
a.cc:14:5: note:                 'int next [1000020][30]'
   14 | int next[N][M],end[N];//trie next[u][id] u结点编号
      |     ^~~~
a.cc:24:25: error: reference to 'next' is ambiguous
   24 |                         next[u][id]=++num;
      |                         ^~~~
/usr/include/c++/14/bits/stl_iterator_base_funcs.h:232:5: note: candidates are: 'template<class _InputIterator> constexpr _InputIterator std::next(_InputIterator, typename iterator_traits<_Iter>::difference_type)'
  232 |     next(_InputIterator __x, typename
      |     ^~~~
a.cc:14:5: note:                 'int next [1000020][30]'
   14 | int next[N][M],end[N];//trie next[u][id] u结点编号
      |     ^~~~
a.cc:26:19: error: reference to 'next' is ambiguous
   26 |                 u=next[u][id];
      |                   ^~~~
/usr/include/c++/14/bits/stl_iterator_base_funcs.h:232:5: note: candidates are: 'template<class _InputIterator> constexpr _InputIterator std::next(_InputIterator, typename iterator_traits<_Iter>::difference_type)'
  232 |     next(_InputIterator __x, typename
      |     ^~~~
a.cc:14:5: note:                 'int next [1000020][30]'
   14 | int next[N][M],end[N];//trie next[u][id] u结点编号
      |     ^~~~
a.cc:28:9: error: reference to 'end' is ambiguous
   28 |         end[u]=x;//单词结束标记
      |         ^~~
In file included from /usr/include/c++/14/string:53:
/usr/include/c++/14/bits/range_access.h:116:37: note: candidates are: 'template<class _Tp> const _Tp* std::end(const valarray<_Tp>&)'
  116 |   template<typename _Tp> const _Tp* end(const valarray<_Tp>&) noexcept;
      |                                     ^~~
/usr/include/c++/14/bits/range_access.h:115:31: note:                 'template<class _Tp> _Tp* std::end(valarray<_Tp>&)'
  115 |   template<typename _Tp> _Tp* end(valarray<_Tp>&) noexcept;
      |                               ^~~
/usr/include/c++/14/bits/range_access.h:106:5: note:                 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::end(_Tp (&)[_Nm])'
  106 |     end(_Tp (&__arr)[_Nm]) noexcept
      |     ^~~
/usr/include/c++/14/bits/range_access.h:85:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(const _Container&)'
   85 |     end(const _Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/bits/range_access.h:74:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(_Container&)'
   74 |     end(_Container& __cont) -> decltype(__cont.end())
      |     ^~~
In file included from /usr/include/c++/14/bits/range_access.h:36:
/usr/include/c++/14/initializer_list:99:5: note:                 'template<class _Tp> constexpr const _Tp* std::end(initializer_list<_Tp>)'
   99 |     end(initializer_list<_Tp> __ils) noexcept
      |     ^~~
a.cc:14:16: note:                 'int end [1000020]'
   14 | int next[N][M],end[N];//trie next[u][id] u结点编号
      |                ^~~
a.cc: In function 'void dfs(int)':
a.cc:46:27: error: reference to 'next' is ambiguous
   46 |                         u=next[u][id];
      |                           ^~~~
/usr/include/c++/14/bits/stl_iterator_base_funcs.h:232:5: note: candidates are: 'template<class _InputIterator> constexpr _InputIterator std::next(_InputIterator, typename iterator_traits<_Iter>::difference_type)'
  232 |     next(_InputIterator __x, typename
      |     ^~~~
a.cc:14:5: note:                 'int next [1000020][30]'
   14 | int next[N][M],end[N];//trie next[u][id] u结点编号
      |     ^~~~
a.cc:51:28: error: reference to 'end' is ambiguous
   51 |                         if(end[u]!=-1)
      |                            ^~~
/usr/include/c++/14/bits/range_access.h:116:37: note: candidates are: 'template<class _Tp> const _Tp* std::end(const valarray<_Tp>&)'
  116 |   template<typename _Tp> const _Tp* end(const valarray<_Tp>&) noexcept;
      |                                     ^~~
/usr/include/c++/14/bits/range_access.h:115:31: note:                 'template<class _Tp> _Tp* std::end(valarray<_Tp>&)'
  115 |   template<typename _Tp> _Tp* end(valarray<_Tp>&) noexcept;
      |                               ^~~
/usr/include/c++/14/bits/range_access.h:106:5: note:                 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::end(_Tp (&)[_Nm])'
  106 |     end(_Tp (&__arr)[_Nm]) noexcept
      |     ^~~
/usr/include/c++/14/bits/range_access.h:85:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(const _Container&)'
   85 |     end(const _Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/bits/range_access.h:74:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(_Container&)'
   74 |     end(_Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/initializer_list:99:5: note:                 'template<class _Tp> constexpr const _Tp* std::end(initializer_list<_Tp>)'
   99 |     end(initializer_list<_Tp> __ils) noexcept
      |     ^~~
a.cc:14:16: note:                 'int end [1000020]'
   14 | int next[N][M],end[N];//trie next[u][id] u结点编号
      |                ^~~
a.cc:53:45: error: reference to 'end' is ambiguous
   53 |                                 dfs(pos+len[end[u]]);//
      |                                             ^~~
/usr/include/c++/14/bits/range_access.h:116:37: note: candidates are: 'template<class _Tp> const _Tp* std::end(const valarray<_Tp>&)'
  116 |   template<typename _Tp> const _Tp* end(const valarray<_Tp>&) noexcept;
      |                                     ^~~
/usr/include/c++/14/bits/range_access.h:115:31: note:                 'template<class _Tp> _Tp* std::end(valarray<_Tp>&)'
  115 |   template<typename _Tp> _Tp* end(valarray<_Tp>&) noexcept;
      |                               ^~~
/usr/include/c++/14/bits/range_access.h:106:5: note:                 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::end(_Tp (&)[_Nm])'
  106 |     end(_Tp (&__arr)[_Nm]) noexcept
      |     ^~~
/usr/include/c++/14/bits/range_access.h:85:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(const _Container&)'
   85 |     end(const _Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/bits/range_access.h:74:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(_Container&)'
   74 |     end(_Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/initializer_list:99:5: note:                 'template<class _Tp> constexpr const _Tp* std::end(initializer_list<_Tp>)'
   99 |     end(initializer_list<_Tp> __ils) noexcept
      |     ^~~
a.cc:14:16: note:                 'int end [1000020]'
   14 | int next[N][M],end[N];//trie next[u][id] u结点编号
      |                ^~~
a.cc: In function 'int main()':
a.cc:61:16: error: reference to 'next' is ambiguous
   61 |         memset(next,0,sizeof(next));
      |                ^~~~
/usr/include/c++/14/bits/stl_iterator_base_funcs.h:232:5: note: candidates are: 'template<class _InputIterator> constexpr _InputIterator std::next(_InputIterator, typename iterator_traits<_Iter>::difference_type)'
  232 |     next(_InputIterator __x, typename
      |     ^~~~
a.cc:14:5: note:                 'int next [1000020][30]'
   14 | int next[N][M],end[N];//trie next[u][id] u结点编号
      |     ^~~~
a.cc:61:30: error: reference to 'next' is ambiguous
   61 |         memset(next,0,sizeof(next));
      |                              ^~~~
/usr/include/c++/14/bits/stl_iterator_base_funcs.h:232:5: note: candidates are: 'template<class _InputIterator> constexpr _InputIterator std::next(_InputIterator, typename iterator_traits<_Iter>::difference_type)'
  232 |     next(_InputIterator __x, typename
      |     ^~~~
a.cc:14:5: note:                 'int next [1000020][30]'
   14 | int next[N][M],end[N];//trie next[u][id] u结点编号
      |     ^~~~
a.cc:62:16: error: reference to 'end' is ambiguous
   62 |         memset(end,-1,sizeof(end));
      |                ^~~
/usr/include/c++/14/bits/range_access.h:116:37: note: candidates are: 'template<class _Tp> const _Tp* std::end(const valarray<_Tp>&)'
  116 |   template<typename _Tp> const _Tp* end(const valarray<_Tp>&) noexcept;
      |                                     ^~~
/usr/include/c++/14/bits/range_access.h:115:31: note:                 'template<class _Tp> _Tp* std::end(valarray<_Tp>&)'
  115 |   template<typename _Tp> _Tp* end(valarray<_Tp>&) noexcept;
      |                               ^~~
/usr/include/c++/14/bits/range_access.h:106:5: note:                 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::end(_Tp (&)[_Nm])'
  106 |     end(_Tp (&__arr)[_Nm]) noexcept
      |     ^~~
/usr/include/c++/14/bits/range_access.h:85:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(const _Container&)'
   85 |     end(const _Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/bits/range_access.h:74:5: note:                 'template<class _Container> constexpr decltype (__cont.end()) std::end(_Container&)'
   74 |     end(_Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/initializer_list: