Language: C++

#include <iostream>
#include <vector>
#include <queue>
using namespace std;

inline void PaintMass(vector<vector<int>>& Mass, queue<pair<int,int>>& Blacks)
{
	const auto& black = Blacks.front();
	const int h = black.first, w = black.second;
  	
  	// 上下左右を塗る
    if( h > 0 && !Mass[h-1][w]){
    	Mass[h-1][w] = true;
      	Blacks.emplace(h-1, w);
    }
          
    if( w > 0 && !Mass[h][w-1]){
        Mass[h][w-1] = true;
       	Blacks.emplace(h, w-1);
    }
          
    if( h < Mass.size() - 1 && !Mass[h+1][w]){
    	Mass[h+1][w] = true;
       	Blacks.emplace(h+1, w);
    }
          
    if( w < Mass[i].size() - 1 && Mass[h][w+1]){
        Mass[h][w+1] = true;
       	Blacks.emplace(h, w)+1;
    }
  
  	Blacks.pop();
}

int main()
{
 	size_t h,w;
 	cin >> h >> w;
	vector<vector<int>> Mass(h, vector<int>(w));
	queue<pair<int,int>> Blacks;
  
	for(size_t i = 0; i < h; ++ i)
    	for(size_t j = 0; j < w; ++ j)
    	{
        	char col;
        	cin >> col;
      		if(Mass[i][j] = col == '#')
            	Blacks.emplace(i, j);
     	}

  	int Paint = 0;
  	while(!Blacks.empty())
    {
    	size_t cnt = Blacks.size();
      	while(cnt)
        {
    		PaintMass(Mass, Blacks);
        }
      	++ Paint;
    }
  
  	cout << Paint;
	return 0; 
}


Compiler output:
a.cc: In function 'void PaintMass(std::vector<std::vector<int> >&, std::queue<std::pair<int, int> >&)':
a.cc:27:18: error: 'i' was not declared in this scope
   27 |     if( w < Mass[i].size() - 1 && Mass[h][w+1]){
      |                  ^
a.cc:29:29: error: no match for 'operator+' (operand types are 'std::pair<int, int>' and 'int')
   29 |         Blacks.emplace(h, w)+1;
      |         ~~~~~~~~~~~~~~~~~~~~^~
      |                       |      |
      |                       |      int
      |                       std::pair<int, int>
In file included from /usr/include/c++/14/string:48,
                 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.h:627:5: note: candidate: 'template<class _Iterator> constexpr std::reverse_iterator<_Iterator> std::operator+(typename reverse_iterator<_Iterator>::difference_type, const reverse_iterator<_Iterator>&)'
  627 |     operator+(typename reverse_iterator<_Iterator>::difference_type __n,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:627:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'int'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^
/usr/include/c++/14/bits/stl_iterator.h:1798:5: note: candidate: 'template<class _Iterator> constexpr std::move_iterator<_IteratorL> std::operator+(typename move_iterator<_IteratorL>::difference_type, const move_iterator<_IteratorL>&)'
 1798 |     operator+(typename move_iterator<_Iterator>::difference_type __n,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1798:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'int'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^
In file included from /usr/include/c++/14/string:54:
/usr/include/c++/14/bits/basic_string.h:3598:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3598 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3598:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   'std::pair<int, int>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^
/usr/include/c++/14/bits/basic_string.h:3616:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3616 |     operator+(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3616:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   mismatched types 'const _CharT*' and 'std::pair<int, int>'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^
/usr/include/c++/14/bits/basic_string.h:3635:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(_CharT, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3635 |     operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Alloc>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3635:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^
/usr/include/c++/14/bits/basic_string.h:3652:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3652 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3652:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   'std::pair<int, int>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^
/usr/include/c++/14/bits/basic_string.h:3670:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, _CharT)'
 3670 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, _CharT __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3670:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   'std::pair<int, int>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^
/usr/include/c++/14/bits/basic_string.h:3682:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3682 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3682:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   'std::pair<int, int>' is not derived from 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^
/usr/include/c++/14/bits/basic_string.h:3689:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3689 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3689:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   'std::pair<int, int>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^
/usr/include/c++/14/bits/basic_string.h:3696:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3696 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3696:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   'std::pair<int, int>' is not derived from 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^
/usr/include/c++/14/bits/basic_string.h:3719:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const _CharT*, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3719 |     operator+(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3719:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   mismatched types 'const _CharT*' and 'std::pair<int, int>'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^
/usr/include/c++/14/bits/basic_string.h:3726:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(_CharT, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3726 |     operator+(_CharT __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3726:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   mismatched types 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^
/usr/include/c++/14/bits/basic_string.h:3733:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, const _CharT*)'
 3733 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3733:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   'std::pair<int, int>' is not derived from 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^
/usr/include/c++/14/bits/basic_string.h:3740:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, _CharT)'
 3740 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3740:5: note:   template argument deduction/substitution failed:
a.cc:29:30: note:   'std::pair<int, int>' is not derived from 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   29 |         Blacks.emplace(h, w)+1;
      |                              ^