Language: C++

#include <iostream>

int main(void){
  	const int N;
	std::cin >> N;
  	int h[N];
  
  	for(int i = 0; i < N; i++){
    	std::cin >> h[i];
    }

  	int count = 0;
  	int start, end;
  
  	bool all_zero = false;
  	while(!all_zero){
      	all_zero = true;
		start = end = 0;
  		while(end < N){
    		if(h[end] == 0){
        		if(start < end){	
              		for(int i = start; i < end; i++){
            			h[i] -= 1;
	            	}
    	      		++count;
                }
              	++end;
              	start = end;
        	}
          	else {
              	all_zero = false;
              	if(end == N-1){
                	for(int i = start; i <= end; i++){
            			h[i] -= 1;
	            	}
    	      		++count;
                }
            	++end;
            }
    	}
    }
  
  	std::cout << count;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:4:19: error: uninitialized 'const N' [-fpermissive]
    4 |         const int N;
      |                   ^
a.cc:5:18: error: no match for 'operator>>' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'const int')
    5 |         std::cin >> N;
      |         ~~~~~~~~ ^~ ~
      |              |      |
      |              |      const int
      |              std::istream {aka std::basic_istream<char>}
In file included from /usr/include/c++/14/iostream:42,
                 from a.cc:1:
/usr/include/c++/14/istream:170:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  170 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:170:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'int'
    5 |         std::cin >> N;
      |                     ^
/usr/include/c++/14/istream:174:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  174 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:174:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: cannot bind non-const lvalue reference of type 'short int&' to a value of type 'int'
    5 |         std::cin >> N;
      |                     ^
/usr/include/c++/14/istream:177:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  177 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:177:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: cannot bind non-const lvalue reference of type 'short unsigned int&' to a value of type 'int'
    5 |         std::cin >> N;
      |                     ^
/usr/include/c++/14/istream:184:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  184 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:184:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: cannot bind non-const lvalue reference of type 'unsigned int&' to a value of type 'int'
    5 |         std::cin >> N;
      |                     ^
/usr/include/c++/14/istream:188:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  188 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:188:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: cannot bind non-const lvalue reference of type 'long int&' to a value of type 'int'
    5 |         std::cin >> N;
      |                     ^
/usr/include/c++/14/istream:192:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  192 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:192:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: cannot bind non-const lvalue reference of type 'long unsigned int&' to a value of type 'int'
    5 |         std::cin >> N;
      |                     ^
/usr/include/c++/14/istream:199:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  199 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:199:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: cannot bind non-const lvalue reference of type 'long long int&' to a value of type 'int'
    5 |         std::cin >> N;
      |                     ^
/usr/include/c++/14/istream:203:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  203 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:203:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: cannot bind non-const lvalue reference of type 'long long unsigned int&' to a value of type 'int'
    5 |         std::cin >> N;
      |                     ^
/usr/include/c++/14/istream:219:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(float&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  219 |       operator>>(float& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:219:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: cannot bind non-const lvalue reference of type 'float&' to a value of type 'int'
    5 |         std::cin >> N;
      |                     ^
/usr/include/c++/14/istream:223:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  223 |       operator>>(double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:223:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: cannot bind non-const lvalue reference of type 'double&' to a value of type 'int'
    5 |         std::cin >> N;
      |                     ^
/usr/include/c++/14/istream:227:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  227 |       operator>>(long double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:227:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: cannot bind non-const lvalue reference of type 'long double&' to a value of type 'int'
    5 |         std::cin >> N;
      |                     ^
/usr/include/c++/14/istream:328:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  328 |       operator>>(void*& __p)
      |       ^~~~~~~~
/usr/include/c++/14/istream:328:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: invalid conversion from 'int' to 'void*' [-fpermissive]
    5 |         std::cin >> N;
      |                     ^
      |                     |
      |                     int
a.cc:5:21: error: cannot bind rvalue '(void*)((long int)((int)N))' to 'void*&'
/usr/include/c++/14/istream:122:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__istream_type& (*)(__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:122:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: invalid conversion from 'int' to 'std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&)' {aka 'std::basic_istream<char>& (*)(std::basic_istream<char>&)'} [-fpermissive]
    5 |         std::cin >> N;
      |                     ^
      |                     |
      |                     int
/usr/include/c++/14/istream:126:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__ios_type& (*)(__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>; __ios_type = std::basic_ios<char>]' (near match)
  126 |       operator>>(__ios_type& (*__pf)(__ios_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:126:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: invalid conversion from 'int' to 'std::basic_istream<char>::__ios_type& (*)(std::basic_istream<char>::__ios_type&)' {aka 'std::basic_ios<char>& (*)(std::basic_ios<char>&)'} [-fpermissive]
    5 |         std::cin >> N;
      |                     ^
      |                     |
      |                     int
/usr/include/c++/14/istream:133:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(std::ios_base& (*)(std::ios_base&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  133 |       operator>>(ios_base& (*__pf)(ios_base&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:133:7: note:   conversion of argument 1 would be ill-formed:
a.cc:5:21: error: invalid conversion from 'int' to 'std::ios_base& (*)(std::ios_base&)' [-fpermissive]
    5 |         std::cin >> N;
      |                     ^
      |                     |
      |                     int
/usr/include/c++/14/istream:181:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std: