Language: C++

#include <iostream>
#include <vector>

using namespace std;

struct Edge {
  int from;
  int to;
  int d;
  E (int from, int to, int d)
    : from(from), to(to), d(d)
  {}
}

class People {
  vector<vector<Edge>> graph;
  vector<int> visited;
  vector<int> total;
  int n;
public:
  People () {
    int m;
    cin >> n >> m;
    graph.resize(n);
    visited.resize(n, 0);
    total.resize(n);
    int l, r, d;
    for (int i=0; i<m; ++i) {
      cin >> l >> r >> d;
      graph[l].emplace_back(l, r, d);
      graph[r].emplace_back(r, l, -d);
    }
  }

  bool visit (int v, int t) {
    if (1 == visited[v]) {
      return t == total[v];
    } else if (0 == visited) {
      total[t] = t;
      visited[v] = 1;
      for (Edge &e : graph[v]) {
        if (!visit(e.to, t + e.d)) {
          return false;
        }
      }
      visited[v] = 2;
      return true;
    }
    return true;
  }
  bool solve () {
    for (int i=0; i<n; ++i) {
      if (!visited[i]) return false;
    }
    return true;
  }
}

int main () {
  People p;
  cout << (p.solve() ? "Yes" : "No") << endl;
  return 0;
}

Compiler output:
a.cc:10:3: error: ISO C++ forbids declaration of 'E' with no type [-fpermissive]
   10 |   E (int from, int to, int d)
      |   ^
a.cc:13:2: error: expected ';' after struct definition
   13 | }
      |  ^
      |  ;
a.cc: In member function 'int Edge::E(int, int, int)':
a.cc:11:7: error: only constructors take member initializers
   11 |     : from(from), to(to), d(d)
      |       ^~~~
a.cc:12:4: warning: no return statement in function returning non-void [-Wreturn-type]
   12 |   {}
      |    ^
a.cc: At global scope:
a.cc:57:2: error: expected ';' after class definition
   57 | }
      |  ^
      |  ;
a.cc: In member function 'bool People::visit(int, int)':
a.cc:38:18: error: no match for 'operator==' (operand types are 'int' and 'std::vector<int>')
   38 |     } else if (0 == visited) {
      |                ~ ^~ ~~~~~~~
      |                |    |
      |                int  std::vector<int>
In file included from /usr/include/c++/14/iosfwd:42,
                 from /usr/include/c++/14/ios:40,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/postypes.h:192:5: note: candidate: 'template<class _StateT> bool std::operator==(const fpos<_StateT>&, const fpos<_StateT>&)'
  192 |     operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/postypes.h:192:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'const std::fpos<_StateT>' and 'int'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
In file included from /usr/include/c++/14/string:43,
                 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:
/usr/include/c++/14/bits/allocator.h:235:5: note: candidate: 'template<class _T1, class _T2> bool std::operator==(const allocator<_CharT>&, const allocator<_T2>&)'
  235 |     operator==(const allocator<_T1>&, const allocator<_T2>&)
      |     ^~~~~~~~
/usr/include/c++/14/bits/allocator.h:235:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'const std::allocator<_CharT>' and 'int'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
In file included from /usr/include/c++/14/string:48:
/usr/include/c++/14/bits/stl_iterator.h:441:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  441 |     operator==(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:441:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'int'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  486 |     operator==(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'int'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1667 |     operator==(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'int'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1737 |     operator==(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'int'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/string:51:
/usr/include/c++/14/bits/stl_pair.h:1033:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator==(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1033 |     operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1033:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'const std::pair<_T1, _T2>' and 'int'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54:
/usr/include/c++/14/string_view:629:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(basic_string_view<_CharT, _Traits>, __type_identity_t<basic_string_view<_CharT, _Traits> >)'
  629 |     operator==(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:629:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'int'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
/usr/include/c++/14/string_view:637:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  637 |     operator==(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:637:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'int'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
/usr/include/c++/14/string_view:644:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(__type_identity_t<basic_string_view<_CharT, _Traits> >, basic_string_view<_CharT, _Traits>)'
  644 |     operator==(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:644:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   'std::vector<int>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
/usr/include/c++/14/bits/basic_string.h:3755:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3755 |     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3755:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
/usr/include/c++/14/bits/basic_string.h:3772:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3772 |     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3772:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
/usr/include/c++/14/bits/basic_string.h:3819:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3819 |     operator==(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3819:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'const _CharT*' and 'int'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
In file included from /usr/include/c++/14/bits/memory_resource.h:47,
                 from /usr/include/c++/14/string:68:
/usr/include/c++/14/tuple:2558:5: note: candidate: 'template<class ... _TElements, class ... _UElements> constexpr bool std::operator==(const tuple<_UTypes ...>&, const tuple<_Elements ...>&)'
 2558 |     operator==(const tuple<_TElements...>& __t,
      |     ^~~~~~~~
/usr/include/c++/14/tuple:2558:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'const std::tuple<_UTypes ...>' and 'int'
   38 |     } else if (0 == visited) {
      |                     ^~~~~~~
In file included from /usr/include/c++/14/bits/locale_facets.h:48,
                 from /usr/include/c++/14/bits/basic_ios.h:37,
                 from /usr/include/c++/14/ios:46:
/usr/include/c++/14/bits/streambuf_iterator.h:234:5: note: candidate: 'template<class _CharT, class _Traits> bool std::operator==(const istreambuf_iterator<_CharT, _Traits>&, const istreambuf_iterator<_CharT, _Traits>&)'
  234 |     operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
      |     ^~~~~~~~
/usr/include/c++/14/bits/streambuf_iterator.h:234:5: note:   template argument deduction/substitution failed:
a.cc:38:21: note:   mismatched types 'const std::istreambuf_iterator<_CharT, _Traits>' and 'int'
   38 |     } e