Language: C++

=#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;

int n;

typedef long long i64;

vector<int> edges[100010];

i64 a[100010];

void input()
{
	cin >> n;
	for(int i = 1;i <= n;i++)
	{
		cin >> a[i];
	}

	for(int i = 0;i < n - 1;i++)
	{
		int s,t;

		cin >> s >> t;

		edges[s].push_back(t);
		edges[t].push_back(s);
	}
}

vector<int> leave;

void get_leave()
{
	for(int i = 1;i <= n;i++)
	{
		if(edges[i].size() == 1)
		{
			leave.push_back(i);
		}
	}
}

vector<int> topolo[100010];

vector<int> deeper;

void get_topolo()
{
	vector<bool> vec(n + 1,false);
	queue<int> que;

	for(int l : leave)
	{
		que.push(l);
	}

	while(!que.empty())
	{
		int v = que.front();
		que.pop();

		if(vec[v]) continue;
		vec[v] = true;
		deeper.push_back(v);

		for(int to : edges[v])
		{
			if(vec[to] == false)
			{
				topolo[to].push_back(v);
				que.push(to);
			}
		}
	}
}

bool solve()
{
	for(int v : deeper)
	{
		//////cout << v << ":";
		//leaf
		if(topolo[v].size() == 0)
		{
		}
		else if(topolo[v].size() == 1)
		{
			int chi = topolo[v][0];
			if(a[chi] != a[v])
			{
				//cout << a[v] << "=" << a[chi] << endl;
				return false;
			}
		}
		else
		{
			//can solve self
			i64 sum = 0;

			for(int chi : topolo[v])
			{
				sum += a[chi];
			}
			
			//cout << endl << "sum" << sum << endl;

			i64 x = 2 * a[v] - sum;

			if(x < 0 || a[v] < x) return false;

			a[v] = x;

			if(deeper[deeper.size() - 1] == v)
			{
				if(x != 0)
				{
					return false;
				}
			}
		}
		//cout << a[v] << endl;
	}
	return true;
}

int main()
{
	input();

	get_leave();

	get_topolo();

	if(solve())
	{
		cout << "YES" << endl;
	}
	else
	{
		cout << "NO" << endl;
	}
	return 0;
}


Compiler output:
a.cc:1:2: error: stray '#' in program
    1 | =#include <iostream>
      |  ^
a.cc:1:1: error: expected unqualified-id before '=' token
    1 | =#include <iostream>
      | ^
In file included from /usr/include/c++/14/bits/char_traits.h:42,
                 from /usr/include/c++/14/string:42,
                 from a.cc:2:
/usr/include/c++/14/bits/postypes.h:68:11: error: 'ptrdiff_t' does not name a type
   68 |   typedef ptrdiff_t     streamsize; // Signed integral type
      |           ^~~~~~~~~
/usr/include/c++/14/bits/postypes.h:41:1: note: 'ptrdiff_t' is defined in header '<cstddef>'; this is probably fixable by adding '#include <cstddef>'
   40 | #include <cwchar> // For mbstate_t
  +++ |+#include <cstddef>
   41 | 
In file included from /usr/include/c++/14/bits/char_traits.h:50:
/usr/include/c++/14/type_traits:666:33: error: 'nullptr_t' is not a member of 'std'
  666 |     struct is_null_pointer<std::nullptr_t>
      |                                 ^~~~~~~~~
/usr/include/c++/14/type_traits:666:42: error: template argument 1 is invalid
  666 |     struct is_null_pointer<std::nullptr_t>
      |                                          ^
/usr/include/c++/14/type_traits:670:48: error: template argument 1 is invalid
  670 |     struct is_null_pointer<const std::nullptr_t>
      |                                                ^
/usr/include/c++/14/type_traits:674:51: error: template argument 1 is invalid
  674 |     struct is_null_pointer<volatile std::nullptr_t>
      |                                                   ^
/usr/include/c++/14/type_traits:678:57: error: template argument 1 is invalid
  678 |     struct is_null_pointer<const volatile std::nullptr_t>
      |                                                         ^
/usr/include/c++/14/type_traits:1429:37: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
 1429 |     : public integral_constant<std::size_t, alignof(_Tp)>
      |                                     ^~~~~~
In file included from /usr/include/wchar.h:35,
                 from /usr/include/c++/14/cwchar:44,
                 from /usr/include/c++/14/bits/postypes.h:40:
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/type_traits:1429:57: error: template argument 1 is invalid
 1429 |     : public integral_constant<std::size_t, alignof(_Tp)>
      |                                                         ^
/usr/include/c++/14/type_traits:1429:57: note: invalid template non-type parameter
/usr/include/c++/14/type_traits:1438:37: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
 1438 |     : public integral_constant<std::size_t, 0> { };
      |                                     ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/type_traits:1438:46: error: template argument 1 is invalid
 1438 |     : public integral_constant<std::size_t, 0> { };
      |                                              ^
/usr/include/c++/14/type_traits:1438:46: note: invalid template non-type parameter
/usr/include/c++/14/type_traits:1440:26: error: 'std::size_t' has not been declared
 1440 |   template<typename _Tp, std::size_t _Size>
      |                          ^~~
/usr/include/c++/14/type_traits:1441:21: error: '_Size' was not declared in this scope
 1441 |     struct rank<_Tp[_Size]>
      |                     ^~~~~
/usr/include/c++/14/type_traits:1441:27: error: template argument 1 is invalid
 1441 |     struct rank<_Tp[_Size]>
      |                           ^
/usr/include/c++/14/type_traits:1442:37: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
 1442 |     : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
      |                                     ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/type_traits:1442:65: error: template argument 1 is invalid
 1442 |     : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
      |                                                                 ^
/usr/include/c++/14/type_traits:1442:65: note: invalid template non-type parameter
/usr/include/c++/14/type_traits:1446:37: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
 1446 |     : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
      |                                     ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/type_traits:1446:65: error: template argument 1 is invalid
 1446 |     : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
      |                                                                 ^
/usr/include/c++/14/type_traits:1446:65: note: invalid template non-type parameter
/usr/include/c++/14/type_traits:2086:26: error: 'std::size_t' has not been declared
 2086 |   template<typename _Tp, std::size_t _Size>
      |                          ^~~
/usr/include/c++/14/type_traits:2087:30: error: '_Size' was not declared in this scope
 2087 |     struct remove_extent<_Tp[_Size]>
      |                              ^~~~~
/usr/include/c++/14/type_traits:2087:36: error: template argument 1 is invalid
 2087 |     struct remove_extent<_Tp[_Size]>
      |                                    ^
/usr/include/c++/14/type_traits:2099:26: error: 'std::size_t' has not been declared
 2099 |   template<typename _Tp, std::size_t _Size>
      |                          ^~~
/usr/include/c++/14/type_traits:2100:35: error: '_Size' was not declared in this scope
 2100 |     struct remove_all_extents<_Tp[_Size]>
      |                                   ^~~~~
/usr/include/c++/14/type_traits:2100:41: error: template argument 1 is invalid
 2100 |     struct remove_all_extents<_Tp[_Size]>
      |                                         ^
/usr/include/c++/14/type_traits:2171:12: error: 'std::size_t' has not been declared
 2171 |   template<std::size_t _Len>
      |            ^~~
/usr/include/c++/14/type_traits:2176:30: error: '_Len' was not declared in this scope
 2176 |         unsigned char __data[_Len];
      |                              ^~~~
/usr/include/c++/14/type_traits:2194:12: error: 'std::size_t' has not been declared
 2194 |   template<std::size_t _Len, std::size_t _Align =
      |            ^~~
/usr/include/c++/14/type_traits:2194:30: error: 'std::size_t' has not been declared
 2194 |   template<std::size_t _Len, std::size_t _Align =
      |                              ^~~
/usr/include/c++/14/type_traits:2195:55: error: '_Len' was not declared in this scope
 2195 |            __alignof__(typename __aligned_storage_msa<_Len>::__type)>
      |                                                       ^~~~
/usr/include/c++/14/type_traits:2195:59: error: template argument 1 is invalid
 2195 |            __alignof__(typename __aligned_storage_msa<_Len>::__type)>
      |                                                           ^
/usr/include/c++/14/type_traits:2202:30: error: '_Len' was not declared in this scope
 2202 |         unsigned char __data[_Len];
      |                              ^~~~
/usr/include/c++/14/type_traits:2203:44: error: '_Align' was not declared in this scope
 2203 |         struct __attribute__((__aligned__((_Align)))) { } __align;
      |                                            ^~~~~~
/usr/include/c++/14/bits/char_traits.h:144:61: error: 'std::size_t' has not been declared
  144 |       compare(const char_type* __s1, const char_type* __s2, std::size_t __n);
      |                                                             ^~~
/usr/include/c++/14/bits/char_traits.h:146:40: error: 'size_t' in namespace 'std' does not name a type
  146 |       static _GLIBCXX14_CONSTEXPR std::size_t
      |                                        ^~~~~~
/usr/include/c++/14/bits/char_traits.h:150:34: error: 'std::size_t' has not been declared
  150 |       find(const char_type* __s, std::size_t __n, const char_type& __a);
      |                                  ^~~
/usr/include/c++/14/bits/char_traits.h:153:52: error: 'std::size_t' has not been declared
  153 |       move(char_type* __s1, const char_type* __s2, std::size_t __n);
      |                                                    ^~~
/usr/include/c++/14/bits/char_traits.h:156:52: error: 'std::size_t' has not been declared
  156 |       copy(char_type* __s1, const char_type* __s2, std::size_t __n);
      |                                                    ^~~
/usr/include/c++/14/bits/char_traits.h:159:30: error: 'std::size_t' has not been declared
  159 |       assign(char_type* __s, std::size_t __n, char_type __a);
      |                              ^~~
/usr/include/c++/14/bits/char_traits.h:187:59: error: 'std::size_t' has not been declared
  187 |     compare(const char_type* __s1, const char_type* __s2, std::size_t __n)
      |                                                           ^~~
/usr/include/c++/14/bits/char_traits.h: In static member function 'static constexpr int __gnu_cxx::char_traits<_CharT>::compare(const char_type*, const char_type*, int)':
/usr/include/c++/14/bits/char_traits.h:189:17: error: 'size_t' is not a member of 'std'; did you mean 'size_t'?
  189 |       for (std::size_t __i = 0; __i < __n; ++__i)
      |                 ^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/14/include/stddef.h:214:23: note: 'size_t' declared here
  214 | typedef __SIZE_TYPE__ size_t;
      |                       ^~~~~~
/usr/include/c++/14/bits/char_traits.h:189:33: error: '__i' was not declared in this scope; did you mean '__n'?
  189 |       for (std::size_t __i = 0; __i < __n; ++__i)
      |                                 ^~~
      |                                 __n
/usr/include/c++/14/bits/char_traits.h: At global scope:
/usr/include/c++/14/bits/char_traits.h:198:31: error: 'size_t' in namespace 'std'