Language: C++

#define _USE_MATH_DEFINES
#include<bits/stdc++.h>
//#define int long long
#define rep(i,n) for(int i=0;i<n;i++)
#define Rep(i,a,b) for(int i=0;i<b;i++)
#define REP(i,a,b) for(int i=0;i<=b;i++)
#define rev(i,n) for(int i=n-1;i>=0;i--)
#define vi vector<int>
#define vvi vector<vi>
#define pb push_back
#define pi pair<int,int>
#define vp vector<pair<int,int>>
#define mp make_pair
#define all(v) (v).begin(),(v).end()
#define fi first
#define se second
#define MEMSET(a) memset(a,0,sizeof(a))
#define inf (1ll<<60)
#define Yes(f) cout <<(f?"Yes":"No")<<endl//fが真の場合Yesを出力、偽の場合Noを出力
#define yes(f) cout <<(f?"yes":"no")<<endl
#define YES(f) cout <<(f?"YES":"NO")<<endl
#define SORT(v) sort(all(v))
#define RSORT(v) sort(all(v),greater<int>())

using namespace std;

const int mod=1e9+7;

//num今の場所の数字
int ans;
int change(int x, int y,int h,int w,int num){
    int hen=0;
    if(x<0||x>=w||y<0||y>=h)
    {
        //hen++;
        return;
    }

    field[y][x]=min(field[y][x],num);

    change(x-1,y,h,w,num+1);
    change(x+1,y,h,w,num+1);
    change(x,y-1,h,w,num+1);
    change(x,y+1,h,w,num+1);
/*
    change[y][x-1];
    change[y][x+1];
    change[y-1][x];
    change[y+1][x];
*/
}


//wをｘ座標として考える
int main(){
    int h,w;
    cin >> h >> w;
    vvi field(h*w,inf);
    int black=0;
    char a;
    int x,y;
    vp black_place(h*w);
    rep(i,h)
    {
        rep(j,w)
        {
            cin >> a;
            if(a=='#'){
                field[i][j]=1;
                black_place[black].fi=j;
                black_place[black].se=i;
                black++;
            }
        }
    }

    //処理
    rep(i,black)
    {
        change(black_place[i].fi,black_place[i].se,h,w,2);
    }

    cout << ans << endl;
}

Compiler output:
a.cc: In function 'int change(int, int, int, int, int)':
a.cc:36:9: error: return-statement with no value, in function returning 'int' [-fpermissive]
   36 |         return;
      |         ^~~~~~
a.cc:39:5: error: 'field' was not declared in this scope
   39 |     field[y][x]=min(field[y][x],num);
      |     ^~~~~
a.cc: In function 'int main()':
a.cc:58:22: error: no matching function for call to 'std::vector<std::vector<int> >::vector(int, long long int)'
   58 |     vvi field(h*w,inf);
      |                      ^
In file included from /usr/include/c++/14/vector:66,
                 from /usr/include/c++/14/functional:64,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53,
                 from a.cc:2:
/usr/include/c++/14/bits/stl_vector.h:707:9: note: candidate: 'template<class _InputIterator, class> std::vector<_Tp, _Alloc>::vector(_InputIterator, _InputIterator, const allocator_type&) [with <template-parameter-2-2> = _InputIterator; _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >]'
  707 |         vector(_InputIterator __first, _InputIterator __last,
      |         ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:707:9: note:   template argument deduction/substitution failed:
a.cc:58:22: note:   deduced conflicting types for parameter '_InputIterator' ('int' and 'long long int')
   58 |     vvi field(h*w,inf);
      |                      ^
/usr/include/c++/14/bits/stl_vector.h:678:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::initializer_list<_Tp>, const allocator_type&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; allocator_type = std::allocator<std::vector<int> >]'
  678 |       vector(initializer_list<value_type> __l,
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:678:43: note:   no known conversion for argument 1 from 'int' to 'std::initializer_list<std::vector<int> >'
  678 |       vector(initializer_list<value_type> __l,
      |              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:659:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&, std::__type_identity_t<_Alloc>&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; std::__type_identity_t<_Alloc> = std::allocator<std::vector<int> >]'
  659 |       vector(vector&& __rv, const __type_identity_t<allocator_type>& __m)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:659:23: note:   no known conversion for argument 1 from 'int' to 'std::vector<std::vector<int> >&&'
  659 |       vector(vector&& __rv, const __type_identity_t<allocator_type>& __m)
      |              ~~~~~~~~~^~~~
/usr/include/c++/14/bits/stl_vector.h:640:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&, const allocator_type&, std::false_type) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; allocator_type = std::allocator<std::vector<int> >; std::false_type = std::false_type]'
  640 |       vector(vector&& __rv, const allocator_type& __m, false_type)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:640:7: note:   candidate expects 3 arguments, 2 provided
/usr/include/c++/14/bits/stl_vector.h:635:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&, const allocator_type&, std::true_type) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; allocator_type = std::allocator<std::vector<int> >; std::true_type = std::true_type]'
  635 |       vector(vector&& __rv, const allocator_type& __m, true_type) noexcept
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:635:7: note:   candidate expects 3 arguments, 2 provided
/usr/include/c++/14/bits/stl_vector.h:624:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(const std::vector<_Tp, _Alloc>&, std::__type_identity_t<_Alloc>&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; std::__type_identity_t<_Alloc> = std::allocator<std::vector<int> >]'
  624 |       vector(const vector& __x, const __type_identity_t<allocator_type>& __a)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:624:28: note:   no known conversion for argument 1 from 'int' to 'const std::vector<std::vector<int> >&'
  624 |       vector(const vector& __x, const __type_identity_t<allocator_type>& __a)
      |              ~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:620:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >]'
  620 |       vector(vector&&) noexcept = default;
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:620:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:601:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(const std::vector<_Tp, _Alloc>&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >]'
  601 |       vector(const vector& __x)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:601:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:569:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(size_type, const value_type&, const allocator_type&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; size_type = long unsigned int; value_type = std::vector<int>; allocator_type = std::allocator<std::vector<int> >]'
  569 |       vector(size_type __n, const value_type& __value,
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:569:47: note:   no known conversion for argument 2 from 'long long int' to 'const std::vector<std::vector<int> >::value_type&' {aka 'const std::vector<int>&'}
  569 |       vector(size_type __n, const value_type& __value,
      |                             ~~~~~~~~~~~~~~~~~~^~~~~~~
/usr/include/c++/14/bits/stl_vector.h:556:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(size_type, const allocator_type&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; size_type = long unsigned int; allocator_type = std::allocator<std::vector<int> >]'
  556 |       vector(size_type __n, const allocator_type& __a = allocator_type())
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:556:51: note:   no known conversion for argument 2 from 'long long int' to 'const std::vector<std::vector<int> >::allocator_type&' {aka 'const std::allocator<std::vector<int> >&'}
  556 |       vector(size_type __n, const allocator_type& __a = allocator_type())
      |                             ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:542:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(const allocator_type&) [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >; allocator_type = std::allocator<std::vector<int> >]'
  542 |       vector(const allocator_type& __a) _GLIBCXX_NOEXCEPT
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:542:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:531:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector() [with _Tp = std::vector<int>; _Alloc = std::allocator<std::vector<int> >]'
  531 |       vector() = default;
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:531:7: note:   candidate expects 0 arguments, 2 provided
a.cc: In function 'int change(int, int, int, int, int)':
a.cc:44:11: warning: control reaches end of non-void function [-Wreturn-type]
   44 |     change(x,y+1,h,w,num+1);
      |     ~~~~~~^~~~~~~~~~~~~~~~~