criyle/codenet-compile-errors huggingface dataset:
Language: C++

#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep2(i, s, n) for (int i = (s); i < (int)(n); i++)
typedef long long ll;

int main() {
    int N;
    bool frag = true;
    cin >> N;
    vector<string> v (N);
    cin >> v.at(0)
    for  (int i = 1; i < N; i++) {
        cin >> v.at(i);
        for (int j = 0; j < i; j++)
        {
            if (v.at(j) == v.at(i)) {
                cout << "No" << endl;
                frag = false;
                break;
            }
        }
        if (v.at(i).at(0) != v.at(i-1)) {
            cout << "No" << endl;
            frag = false;
            break;
        
    }
    if (frag) {
        cout << "Yes" << endl;
    }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:12:19: error: expected ';' before 'for'
   12 |     cin >> v.at(0)
      |                   ^
      |                   ;
   13 |     for  (int i = 1; i < N; i++) {
      |     ~~~            
a.cc:13:22: error: 'i' was not declared in this scope
   13 |     for  (int i = 1; i < N; i++) {
      |                      ^
a.cc:32:2: error: expected '}' at end of input
   32 | }
      |  ^
a.cc:7:12: note: to match this '{'
    7 | int main() {
      |            ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep2(i, s, n) for (int i = (s); i < (int)(n); i++)
typedef long long ll;

int main() {
    int N;
    bool frag = true;
    cin >> N;
    vector<str> v (N);
    cin >> v.at(0)
    for  (int i = 1; i < N; i++) {
        cin >> v.at(i);
        for (int j = 0; j < i; j++)
        {
            if (v.at(j) == v.at(i)) {
                cout << "No" << endl;
                frag = false;
                break;
            }
        }
        if (v.at(i).at(0) != v.at(i-1)) {
            cout << "No" << endl;
            frag = false;
            break;
        
    }
    if (frag) {
        cout << "Yes" << endl;
    }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:11:12: error: 'str' was not declared in this scope; did you mean 'std'?
   11 |     vector<str> v (N);
      |            ^~~
      |            std
a.cc:11:15: error: template argument 1 is invalid
   11 |     vector<str> v (N);
      |               ^
a.cc:11:15: error: template argument 2 is invalid
a.cc:12:14: error: request for member 'at' in 'v', which is of non-class type 'int'
   12 |     cin >> v.at(0)
      |              ^~
a.cc:13:22: error: 'i' was not declared in this scope
   13 |     for  (int i = 1; i < N; i++) {
      |                      ^
a.cc:32:2: error: expected '}' at end of input
   32 | }
      |  ^
a.cc:7:12: note: to match this '{'
    7 | int main() {
      |            ^
Language: Java

import java.util.*;
public class Main{
	public static void main(String[] args){
    	Scanner sc = new Scanner(System.in);
      int n = sc.nextInt();
      String[] str = new String[n];
      boolean count = true;
      for(int i = 0;i < n;i++){
      	str[i] = sc.next();
      }
      for(int i = 1;i < n;i++){
      	for(int j = 0;j < i;j++){
        	if( str[i].equals(str[j]) ) count = false;
        }
      }
      for(int i = 1;i < n;i++){
      	if(!(str[i-1].substring(str[i-1].length()-1,str[i-1].length()).equals(str[i].substring(0,1)) ))
          count = false;
      }
      if(count)System.out.println(Yes);
      else System.out.println(No);
    }
}

Compiler output:
Main.java:20: error: cannot find symbol
      if(count)System.out.println(Yes);
                                  ^
  symbol:   variable Yes
  location: class Main
Main.java:21: error: cannot find symbol
      else System.out.println(No);
                              ^
  symbol:   variable No
  location: class Main
2 errors
Language: Java

import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		String pre = "", str = "", ans = "Yes";

		for (int i = 0; i < n; i++) {
			str = sc.next();
			if (i > 0 && (!pre.endsWith(str.substring(0, 1)) || pre.contains("\"+str))) {
				ans = "No";
			} else {
				pre += "\"+str;
			}
		}
		
		

		System.out.println(ans);
		sc.close();
	}

}


Compiler output:
Main.java:11: error: unclosed string literal
			if (i > 0 && (!pre.endsWith(str.substring(0, 1)) || pre.contains("\"+str))) {
			                                                                 ^
Main.java:14: error: unclosed string literal
				pre += "\"+str;
				       ^
Main.java:13: error: 'else' without 'if'
			} else {
			  ^
Main.java:20: error: <identifier> expected
		System.out.println(ans);
		                  ^
Main.java:20: error: <identifier> expected
		System.out.println(ans);
		                      ^
Main.java:21: error: <identifier> expected
		sc.close();
		        ^
Main.java:24: error: class, interface, enum, or record expected
}
^
7 errors
Language: C++

#include <bits/stdc++.h>
using namespace std;
using vi = vector<int>;
using vb = vector<bool>;
using vc = vector<char>;
using vs = vector<string>;
using vvi = vector<vector<int>>;
using vvc = vector<vector<char>>;
using pii = pair<int, int>;
#define rep(i,n) for(int i=0; i<(int)(n);i++)

int main(){
  int n;
  cin >> n;
  vs w(n);
  rep(i,n){
    cin >> w.at(i);
  }
  set<string> s;
  s.insert(w.at(0));
  for(int i=1;i<n;i++){
    if(s.count(w.at(i))){
      cout << "No" << endl;
      return 0;
    }
    s.insert(w.at(i));
    int pp = w.at(i-1).size()
    if(w.at(i).at(0) != w.at(i-1).at(pp-1)){
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:28:5: error: expected ',' or ';' before 'if'
   28 |     if(w.at(i).at(0) != w.at(i-1).at(pp-1)){
      |     ^~
Language: C++

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep1(i,n) for(int i=1;i<(int)(n);i++)
#define fs first
#define sc second
typedef pair<ll, ll> l_l;
#define EPS (1e-7)
#define INF (1e9)
#define PI (acos(-1))
int main(){
  int n;
  cin>>n;
  vector<string> s(n);
  rep(i,n)cin>>s[i];
  bool f=true;
  rep(i,n-1)if(s[i].back()!=s[i+1].front) f=false;
  set<string> a;
  rep(i,n)
  a.insert(s[i]);
  bool b=true;
  if(a.size()!=s.size())b=false;
  if(f&&b)
  cout <<"Yes"<<endl;
  else cout<<"No"<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:18:27: error: invalid operands of types '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'} and '<unresolved overloaded function type>' to binary 'operator!='
   18 |   rep(i,n-1)if(s[i].back()!=s[i+1].front) f=false;
      |                ~~~~~~~~~~~^~
      |                         |
      |                         __gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type {aka char}
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  int A,D=1;
  cin >> A;
  vector<string>W(A);
  for(int i=0;i<A;i++)cin >> W[i];
  for(int i=0;i<A;i++){
    for(int j=i+1;j<A;j++){
      if(D){
        if(W[i]==W[j]){
          D=0;
          break;
        }
      }
    }
   for(int i=0;i<A-1;i++){
     int B=W[i].size();
     if(W[i][B-1]!=W[i+1][0]){
       D=0;
       break;
     }
   }
   if(D)cout << "Yes" << endl;
    else cout << "No" << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:26:2: error: expected '}' at end of input
   26 | }
      |  ^
a.cc:3:11: note: to match this '{'
    3 | int main(){
      |           ^
Language: C++

#include <bits/stdc++.h>
using namespace std; 

int main() {
    int n,count=0; cin >> n;
    string w[n];
    for(int i=0;i<n;i++) {
        cin >> w[i];
    }
     for(int i=0; i<n;i++){
         for(int j=0;j<n;j++) {
             if(i!=j && w[i]==w[j]) {
                 count++;
             }
         }
     }
    for(int i=0;i<n-1;i++){
        if(i!=n-2 && w[i].at(w[i].size())!=w[i+1].at(0)) {
            count++;
        }
        if(i==n-2 && w[i].at(w[i].size())!=w[n].at(0))
    }
    if(count>0) {
        cout << "No" << endl;
    }
    else {
        cout << "Yes" << endl;
    }
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:22:5: error: expected primary-expression before '}' token
   22 |     }
      |     ^
Language: C++

#include <bits/stdc++.h>
using namespace std; 

int main() {
    int n,count=0; cin >> n;
    string w[n];
    for(int i=0;i<n;i++) {
        cin >> w[i];
    }
     for(int i=0; i<n;i++){
         for(int j=0;j<n;j++) {
             if(i!=j && w[i]==w[j]) {
                 count++;
             }
         }
     }
    for(int i=0;i<n;i++){
        if(i!=n-1 && w[i].at(w[i].size())!=w[i+1].at(0)) {
            count++;
        }
        if(i==n-1 && w[i].at(w[i].size())!=w[n].at(0))
    }
    if(count>0) {
        cout << "No" << endl;
    }
    else {
        cout << "Yes" << endl;
    }
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:22:5: error: expected primary-expression before '}' token
   22 |     }
      |     ^
Language: C++

#include <bits/stdc++.h>
using namespace std; 

int main() {
    int n,count=0; cin >> n;
    string w[n];
    for(int i=0;i<n;i++) {
        cin >> w[i];
    }
     for(int i=0; i<n;i++){
         for(int j=0;j<n;j++) {
             if(w[i]==w[j]) {
                 count++;
             }
         }
     }
    for(int i=-1;i<n-1;i++){
        if(w[i+1].at(w[i+1].size())!=w[i+2].at(0)) {
            count++;
        }
    }
    if(count>0) {
        cout << "No" << endl;
    }
    else {
        cout << "Yes" << endl;
    }
    return 0:
}

Compiler output:
a.cc: In function 'int main()':
a.cc:28:13: error: expected ';' before ':' token
   28 |     return 0:
      |             ^
      |             ;
a.cc:28:13: error: expected primary-expression before ':' token
Language: C++

#include <bits/stdc++.h>
using namespace std; 

int main() {
    int n,count=0; cin >> n;
    string w[n];
    for(int i=0;i<n;i++) {
        cin >> w[i];
    }
     for(int i=0; i<n;i++){
         for(int j=0;j<n;j++) {
             if(w[i]==w[j]) {
                 count++;
             }
         }
 }     }
    for(int i=-1;i<n-1;i++){
        if(w[i+1].at(w[i+1].size())!=w[i+2].at(0)) {
            count++;
        }
    }
    if(count>0) {
        cout << "No" << endl;
    }
    else {
        cout << "Yes" << endl;
    }
    return 0:
}

Compiler output:
a.cc:17:5: error: expected unqualified-id before 'for'
   17 |     for(int i=-1;i<n-1;i++){
      |     ^~~
a.cc:17:18: error: 'i' does not name a type
   17 |     for(int i=-1;i<n-1;i++){
      |                  ^
a.cc:17:24: error: 'i' does not name a type
   17 |     for(int i=-1;i<n-1;i++){
      |                        ^
a.cc:22:5: error: expected unqualified-id before 'if'
   22 |     if(count>0) {
      |     ^~
a.cc:25:5: error: expected unqualified-id before 'else'
   25 |     else {
      |     ^~~~
a.cc:28:5: error: expected unqualified-id before 'return'
   28 |     return 0:
      |     ^~~~~~
a.cc:29:1: error: expected declaration before '}' token
   29 | }
      | ^
Language: C++

#include "bits/stdc++.h"
#define ll long long
#define ALL(v) (v).begin(),(v).end()
#define MOD 1000000007
using namespace std;




int main(){
ll n;
ll ans=0;
cin>>n;
vector<string> a(n);
for(ll i=0;i<n;i++)cin>>a[i];

for(ll i=1;i<n;i++){
if(a[i-1][a[i-1].end()]!=a[i][0]){
  cout<<"No"<<endl;
  return 0;
}

for(ll j=0;j<i;j++){

if(a[j]==a[i]){
  cout<<"No"<<endl;
  return 0;
}


}




}

cout<<"Yes"<<endl;

return 0;

}


Compiler output:
a.cc: In function 'int main()':
a.cc:18:10: error: no match for 'operator[]' (operand types are '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} and 'std::__cxx11::basic_string<char>::iterator')
   18 | if(a[i-1][a[i-1].end()]!=a[i][0]){
      |          ^
In file included from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:1:
/usr/include/c++/14/bits/basic_string.h:1247:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::const_reference std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::operator[](size_type) const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; const_reference = const char&; size_type = long unsigned int]'
 1247 |       operator[] (size_type __pos) const _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:1247:29: note:   no known conversion for argument 1 from 'std::__cxx11::basic_string<char>::iterator' to 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'}
 1247 |       operator[] (size_type __pos) const _GLIBCXX_NOEXCEPT
      |                   ~~~~~~~~~~^~~~~
/usr/include/c++/14/bits/basic_string.h:1265:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::reference std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::operator[](size_type) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; reference = char&; size_type = long unsigned int]'
 1265 |       operator[](size_type __pos)
      |       ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:1265:28: note:   no known conversion for argument 1 from 'std::__cxx11::basic_string<char>::iterator' to 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'}
 1265 |       operator[](size_type __pos)
      |                  ~~~~~~~~~~^~~~~
Language: C++

#include "bits/stdc++.h"
#define ll long long
#define ALL(v) (v).begin(),(v).end()
#define MOD 1000000007
using namespace std;




int main(){
ll n;
ll ans=0;
cin>>n;
vector<string> w(n);
for(ll i=0;i<n;i++)cin>>w[i];

for(ll i=1;i<n;i++){
if(a[i-1][a[i-1].end()]!=a[i][0]){
  cout<<"No"<<endl;
  return 0;
}

for(ll j=0;j<i;j++){

if(a[j]==a[i]){
  cout<<"No"<<endl;
  return 0;
}


}




}

cout<<"Yes"<<endl;

return 0;

}


Compiler output:
a.cc: In function 'int main()':
a.cc:18:4: error: 'a' was not declared in this scope
   18 | if(a[i-1][a[i-1].end()]!=a[i][0]){
      |    ^
a.cc:25:4: error: 'a' was not declared in this scope
   25 | if(a[j]==a[i]){
      |    ^
Language: C++

#include<iostream>
#include<map>
using namespace std;

int main(){
    int n;
    cin >> n;
    string s;
    cin >> s;
    map<string> used;
    used.insert(s);
    for(int i = 1; i < n; i++){
        string t;   cin >> t;
        if(used.count(t) || s[s.length()-1] != t[0]){
            cout << "No" << endl;
            return 0;
        }
        used.count(t);
        s = t;
    }
    cout << "Yes" << endl;
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:15: error: wrong number of template arguments (1, should be at least 2)
   10 |     map<string> used;
      |               ^
In file included from /usr/include/c++/14/map:63,
                 from a.cc:2:
/usr/include/c++/14/bits/stl_map.h:102:11: note: provided for 'template<class _Key, class _Tp, class _Compare, class _Alloc> class std::map'
  102 |     class map
      |           ^~~
a.cc:11:10: error: request for member 'insert' in 'used', which is of non-class type 'int'
   11 |     used.insert(s);
      |          ^~~~~~
a.cc:14:17: error: request for member 'count' in 'used', which is of non-class type 'int'
   14 |         if(used.count(t) || s[s.length()-1] != t[0]){
      |                 ^~~~~
a.cc:18:14: error: request for member 'count' in 'used', which is of non-class type 'int'
   18 |         used.count(t);
      |              ^~~~~
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main()
{
	int n;
  	cin>>n;
  	maps<string,bool> appeared;
  	string before,after;
  	cin>>before;
  	appeared[before]=true;
  	for(int i=1 ; i<n ; ++i)
    {
    	cin>>after;
      	if(appeared[after] && after[0]==before[before.length()-1])
        {
        	cout<<"No"<<endl;
          	return 0;
        }
	    before=after;
    }
	cout<<"Yes"<<endl;
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:9: error: 'maps' was not declared in this scope
    8 |         maps<string,bool> appeared;
      |         ^~~~
a.cc:8:20: error: expected primary-expression before ',' token
    8 |         maps<string,bool> appeared;
      |                    ^
a.cc:8:21: error: expected primary-expression before 'bool'
    8 |         maps<string,bool> appeared;
      |                     ^~~~
a.cc:11:9: error: 'appeared' was not declared in this scope
   11 |         appeared[before]=true;
      |         ^~~~~~~~
Language: C++

require 'set'

n=gets.to_i
a=n.times.map{gets.chomp}
s=Set[*a]

flag=s.size==n
for i in 0...(n-1)
  if a[i][-1]!=a[i+1][0]
    flag=false
  end
end
  
puts flag ? "Yes" : "No"

Compiler output:
a.cc:1:9: warning: multi-character character constant [-Wmultichar]
    1 | require 'set'
      |         ^~~~~
a.cc:8:10: error: too many decimal points in number
    8 | for i in 0...(n-1)
      |          ^~~~
a.cc:1:1: error: 'require' does not name a type
    1 | require 'set'
      | ^~~~~~~
a.cc:5:1: error: 's' does not name a type
    5 | s=Set[*a]
      | ^
Language: C++

#include<iostream>
#include<string>
using namespace std;

int main(){
  int n,i,k; cin>>n;
  stirng s[n];
  bool f=true;
  
  for(i=0;i<n;i++) cin>>s[i];
  for(k=0:k<n-1;k++){
        if(s[i].back() != s[i+1].front()) f = false;
  }
  
  for(i=0;i<n-1;i++){
    for(j=i+1;j<n;j++){
      if(s[i]==s[j]) f=false;
    }
  }
  
  if(f) cout<<"Yes"<<endl;
  else cout<<"Bad"<<endl;
  
  return 0;
}
  

Compiler output:
a.cc: In function 'int main()':
a.cc:7:3: error: 'stirng' was not declared in this scope
    7 |   stirng s[n];
      |   ^~~~~~
a.cc:10:25: error: 's' was not declared in this scope
   10 |   for(i=0;i<n;i++) cin>>s[i];
      |                         ^
a.cc:11:10: error: expected ';' before ':' token
   11 |   for(k=0:k<n-1;k++){
      |          ^
      |          ;
a.cc:11:20: error: expected ';' before ')' token
   11 |   for(k=0:k<n-1;k++){
      |                    ^
      |                    ;
a.cc:12:12: error: 's' was not declared in this scope
   12 |         if(s[i].back() != s[i+1].front()) f = false;
      |            ^
a.cc:16:9: error: 'j' was not declared in this scope
   16 |     for(j=i+1;j<n;j++){
      |         ^
a.cc:17:10: error: 's' was not declared in this scope
   17 |       if(s[i]==s[j]) f=false;
      |          ^
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main()
{
  set<string> s;
  string last,curr;
  bool valid = true;
  int n;
  cin>>n;
  cin>>last;
  s.insert(last);
  n--;
  while(n--)
  {
    cin>>curr;
    if(s.find(curr) != s.end())
      valid=false;
    int len = last.length();
    if(curr[0] != last[len-1])
      valid = false;
    s.insert(curr);
    last = curr;
  }
  if(valid)
    cout<<"Yes";
  else
    cout<<"No";
  return 0;

Compiler output:
a.cc: In function 'int main()':
a.cc:29:12: error: expected '}' at end of input
   29 |   return 0;
      |            ^
a.cc:5:1: note: to match this '{'
    5 | {
      | ^
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main()
{
  set<string> s;
  string last,curr;
  bool valid = true;
  int n;
  cin>>n;
  cin>>last;
  s.insert(last);
  n--;
  while(n--)
  {
    cin>>curr;
    if(s.find(curr) != s.end())
      valid=false;
    int len = last.length();
    if(curr[0] != last[len-1])
      valid = false;
    last = curr;
  }
  if(valid)
    cout<<"Yes";
  else
    cout<<"No";
  return 0;

Compiler output:
a.cc: In function 'int main()':
a.cc:28:12: error: expected '}' at end of input
   28 |   return 0;
      |            ^
a.cc:5:1: note: to match this '{'
    5 | {
      | ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const double pi = acos(-1);
#define FOR(i,a,b) for (ll i=(a),__last_##i=(b);i<__last_##i;i++)
#define RFOR(i,a,b) for (ll i=(b)-1,__last_##i=(a);i>=__last_##i;i--)
#define REP(i,n) FOR(i,0,n)
#define RREP(i,n) RFOR(i,0,n)
#define __GET_MACRO3(_1, _2, _3, NAME, ...) NAME
#define rep(...) __GET_MACRO3(__VA_ARGS__, FOR, REP)(__VA_ARGS__)
#define rrep(...) __GET_MACRO3(__VA_ARGS__, RFOR, RREP)(__VA_ARGS__)
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v) {
REP(i,v.size()){if(i)os<<" ";os<<v[i];}return os;}
template<typename T> ostream& operator<<(ostream& os, const vector<vector<T>>& v) {
REP(i,v.size()){if(i)os<<endl;os<<v[i];}return os;}

int main() {
	int n; cin >> n;
	std::vector<string> v;
	bool ans = true;
	v.push_back(s);
	for (int i = 0; i < n; ++i)
	{
		string s; cin >> s;
		if (i>0 && v[i-1][v[i-1].size()-1] != v[i][0]) ans = false;
	
    }

	if (ans) cout << "Yes" << endl;
	else cout << "No" << endl;

	

}

Compiler output:
a.cc: In function 'int main()':
a.cc:21:21: error: 's' was not declared in this scope
   21 |         v.push_back(s);
      |                     ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const double pi = acos(-1);
#define FOR(i,a,b) for (ll i=(a),__last_##i=(b);i<__last_##i;i++)
#define RFOR(i,a,b) for (ll i=(b)-1,__last_##i=(a);i>=__last_##i;i--)
#define REP(i,n) FOR(i,0,n)
#define RREP(i,n) RFOR(i,0,n)
#define __GET_MACRO3(_1, _2, _3, NAME, ...) NAME
#define rep(...) __GET_MACRO3(__VA_ARGS__, FOR, REP)(__VA_ARGS__)
#define rrep(...) __GET_MACRO3(__VA_ARGS__, RFOR, RREP)(__VA_ARGS__)
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v) {
REP(i,v.size()){if(i)os<<" ";os<<v[i];}return os;}
template<typename T> ostream& operator<<(ostream& os, const vector<vector<T>>& v) {
REP(i,v.size()){if(i)os<<endl;os<<v[i];}return os;}

int main() {
	int n; cin >> n;
	std::vector<string> v;
	bool ans = true;
	for (int i = 0; i < n; ++i)
	{
		string s; cin >> s;
		if (i>0 && v[i-1][v[i-1].size()-1] != v[i][0];) ans = false;
		v.push_back(s);
	}

	if (ans) cout << "Yes" << endl;
	else cout << "No" << endl;

	

}

Compiler output:
a.cc: In function 'int main()':
a.cc:24:63: error: expected primary-expression before ')' token
   24 |                 if (i>0 && v[i-1][v[i-1].size()-1] != v[i][0];) ans = false;
      |                                                               ^
Language: C++

#include <bits/stdc++.h>
using namespace std;

#define REP(i, n) for(int i=0; i<n;i++)
#define REPR(i, n) for(int i=n-1 ; i>=0; i--)
#define FOR(i, m, n) for(int i=m; i<n; i++)

#define INF 2e9
#define ll long long

int main(){
    int n;
    cin>>n;
    string w[n];
    REP(i, n){
        w[i] = "";
    }
    REP(i, n){
        cin>>w[i];
    }
    for(i=1; i<n; i++){
        if(w[i-1][w[i].length()]==w[i][0]){

        }
        else{
            cout<<"No"<<endl;
            return 0;
        }
        
        for(j=0; j<=i; j++){
            if(w[i]==w[j]){
                cout<<"No"<<endl;
                return 0;
            }
        }
    }

    cout<<"Yes"<<endl;

    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:21:9: error: 'i' was not declared in this scope
   21 |     for(i=1; i<n; i++){
      |         ^
a.cc:30:13: error: 'j' was not declared in this scope
   30 |         for(j=0; j<=i; j++){
      |             ^
Language: C++

#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
int main(){
  int n, i;
  cin >> n;
  char w[n][120];
  for(i=0; i<n; i++)
    cin >> w[i];
  for(i=0; i<n-1; i++)
    if(w[i][strlen(w[i])-1]!=w[i+1][0]){
      cout << "No";
      return 0;
    }
  /*  sort(w, w+n);
  for(i=0; i<n-1;i++)
    if(strcmp(w[i], w[i+1])==0){
      cout << "No";
      return 0; */
  for(i=1;i<n; i++)
    for(j=0;j<i; j++){
      if(strcmp(w[i],w[j])==0){
	cout << "No";
	return 0;
      }
    }
  cout << "Yes";
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:22:9: error: 'j' was not declared in this scope
   22 |     for(j=0;j<i; j++){
      |         ^
Language: C++

#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
int main(){
  int n, i;
  cin >> n;
  char w[n][];
  for(i=0; i<n; i++)
    cin >> w[i];
  for(i=0; i<n-1; i++)
    if(w[i][strlen(w[i])-1]!=w[i+1][0]){
      cout << "No";
      return 0;
    }
  sort(w, w+n);
  for(i=0; i<n-1)
    if(strcmp(w[i], w[i+1])==0){
      cout << "No";
      return 0;
    }
  cout << "Yes";
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:8: error: declaration of 'w' as multidimensional array must have bounds for all dimensions except the first
    8 |   char w[n][];
      |        ^
a.cc:10:12: error: 'w' was not declared in this scope
   10 |     cin >> w[i];
      |            ^
a.cc:12:8: error: 'w' was not declared in this scope
   12 |     if(w[i][strlen(w[i])-1]!=w[i+1][0]){
      |        ^
a.cc:16:8: error: 'w' was not declared in this scope
   16 |   sort(w, w+n);
      |        ^
a.cc:17:17: error: expected ';' before ')' token
   17 |   for(i=0; i<n-1)
      |                 ^
      |                 ;
Language: C++

#include <iostream>
#include <string>
#include <functional>
#include <algorithm>

using namespace std;

int main()
{
	string n;
  int sum;
  cin>>n;
  for(int i=1;i<=15;i++){
    if(n.at(i)="o")
      sum++;}
  if(sum>7)
    cout<<"YES"<<endl;
  else
    cout<<"NO"<<endl;
  
    

}


Compiler output:
a.cc: In function 'int main()':
a.cc:14:16: error: invalid conversion from 'const char*' to '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'} [-fpermissive]
   14 |     if(n.at(i)="o")
      |                ^~~
      |                |
      |                const char*
Language: C++

#include<iostream>
#include<algorithm>
#include<cmath>
#include<vector>
using namespace std;
int main() {
  int n,cnt=0;
  vector<string> s(n);
  cin >> n;
  for(int i=0; i<n; i++) {
    cin >> s[i];
  }
  for(int i=0; i<n-1; i++) {
    if(s[i][s.length()-1]!=s[i+1][0]) {
      cnt++;
    }
  }
  for(int i=0; i<n-1; i++) {
    for(int j=i+1; j<n; j++) {
      if(s[i]==s[j]) {
        cnt++;
      }
    }
  }
  if(cnt!=0) {
    cout << "No" << endl;
  }
  else {
    cout << "Yes" << endl;
  }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:14:15: error: 'class std::vector<std::__cxx11::basic_string<char> >' has no member named 'length'
   14 |     if(s[i][s.length()-1]!=s[i+1][0]) {
      |               ^~~~~~
Language: C++

#include<iostream>
#include<algorithm>
#include<cmath>
using namespace std;
int main() {
  int n,cnt=0;
  vector<string> s(n);
  cin >> n;
  for(int i=0; i<n; i++) {
    cin >> s[i];
  }
  for(int i=0; i<n-1; i++) {
    if(s[i][s.length()-1]!=s[i+1][0]) {
      cnt++;
    }
  }
  for(int i=0; i<n-1; i++) {
    for(int j=i+1; j<n; j++) {
      if(s[i]==s[j]) {
        cnt++;
      }
    }
  }
  if(cnt!=0) {
    cout << "No" << endl;
  }
  else {
    cout << "Yes" << endl;
  }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:7:3: error: 'vector' was not declared in this scope
    7 |   vector<string> s(n);
      |   ^~~~~~
a.cc:4:1: note: 'std::vector' is defined in header '<vector>'; this is probably fixable by adding '#include <vector>'
    3 | #include<cmath>
  +++ |+#include <vector>
    4 | using namespace std;
a.cc:7:16: error: expected primary-expression before '>' token
    7 |   vector<string> s(n);
      |                ^
a.cc:7:18: error: 's' was not declared in this scope
    7 |   vector<string> s(n);
      |                  ^
Language: C++

#include<iostream>
#include<algorithm>
#include<cmath>
using namespace std;
int main() {
  int n,cnt=0;
  string s;
  cin >> n >> s;
  for(int i=0; i<n; i++) {
    cin >> s;
  }
  for(int i=0; i<n-1; i++) {
    if(s[i][s.length()-1]!=s[i+1][0]) {
      cnt++;
    }
  }
  for(int i=0; i<n-1; i++) {
    for(int j=i+1; j<n; j++) {
      if(s[i]==s[j]) {
        cnt++;
      }
    }
  }
  if(cnt!=0) {
    cout << "No" << endl;
  }
  else {
    cout << "Yes" << endl;
  }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:13:12: error: invalid types '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type {aka char}[std::__cxx11::basic_string<char>::size_type {aka long unsigned int}]' for array subscript
   13 |     if(s[i][s.length()-1]!=s[i+1][0]) {
      |            ^
a.cc:13:34: error: invalid types '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type {aka char}[int]' for array subscript
   13 |     if(s[i][s.length()-1]!=s[i+1][0]) {
      |                                  ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main() {
  int N;
  cin>>N;
  
  vector<string> vec(N);
  
  for(int i=0;i<N;i++){
    cin>>vec.at(i);
  }
  
  int sum=0;
  
  for(int i=1;i<=N;i++){
  if(vec.at(i).at(vec.at(i).size()-1)!=vec.at(i-1).at(vec.at(i-1)size)){
    sum++;
  }
  }
  
  if(sum==0){
cout<<"Yes"<<endl;
  }
  else{
    cout<<"No"<<endl;
    }
    
}

    
   

Compiler output:
a.cc: In function 'int main()':
a.cc:17:66: error: expected ')' before 'size'
   17 |   if(vec.at(i).at(vec.at(i).size()-1)!=vec.at(i-1).at(vec.at(i-1)size)){
      |                                                      ~           ^~~~
      |                                                                  )
a.cc:17:54: error: no matching function for call to 'std::__cxx11::basic_string<char>::at(__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type&)'
   17 |   if(vec.at(i).at(vec.at(i).size()-1)!=vec.at(i-1).at(vec.at(i-1)size)){
      |                                        ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:1:
/usr/include/c++/14/bits/basic_string.h:1287:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::const_reference std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::at(size_type) const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; const_reference = const char&; size_type = long unsigned int]'
 1287 |       at(size_type __n) const
      |       ^~
/usr/include/c++/14/bits/basic_string.h:1287:20: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} to 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'}
 1287 |       at(size_type __n) const
      |          ~~~~~~~~~~^~~
/usr/include/c++/14/bits/basic_string.h:1309:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::reference std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::at(size_type) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; reference = char&; size_type = long unsigned int]'
 1309 |       at(size_type __n)
      |       ^~
/usr/include/c++/14/bits/basic_string.h:1309:20: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::__cxx11::basic_string<char> >, std::__cxx11::basic_string<char> >::value_type' {aka 'std::__cxx11::basic_string<char>'} to 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'}
 1309 |       at(size_type __n)
      |          ~~~~~~~~~~^~~
Language: C++

#include <bits/stdc++.h>
#define FI first
#define SE second
#define EPS 1e-9
#define ALL(a) a.begin(),a.end()
#define SZ(a) int((a).size())
#define MS(s, n) memset(s, n, sizeof(s))
#define FOR(i,a,b) for (int i = (a); i <= (b); i++)
#define FORE(i,a,b) for (int i = (a); i >= (b); i--)
#define FORALL(it, a) for (__typeof((a).begin()) it = (a).begin(); it != (a).end(); it++)
#define WHATIS(x) cout << #x << " is " << x << endl;
#define ERROR(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it, args); }
//__builtin_ffs(x) return 1 + index of least significant 1-bit of x
//__builtin_clz(x) return number of leading zeros of x
//__builtin_ctz(x) return number of trailing zeros of x

using namespace std;
using ll = long long;
using ld = double;
typedef pair<int, int> II;
typedef pair<ll, II> III;
typedef complex<ld> cd;
typedef vector<cd> vcd;

void err(istream_iterator<string> it) {}
template<typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
    cout << *it << " = " << a << endl;
    err(++it, args...);
}

const ll MODBASE = 1000000007LL;
const int MAXN = 400010;
const int MAXM = 100010;
const int MAXK = 510;
const int MAXQ = 200010;

int n;
string s, pre;
map<string, bool> ma;

int main() {
    ios::sync_with_stdio(0);
    cin.tie(nullptr);
    cin >> n;
  FOR(i,1,n) {
    cin >> s;
    if (i == 1) {
   		ma[s];
	    pre = s;
    }
    else {
      if (ma.count(s)) {
        cout << "No";
        return 0;
      }
      if (s[0] != pre[SZ(pre)-1]) {
        cout << "No";
        return 0;
      }
      ma[s];
      pre = s;
    }
    cout << "Yes";
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:66:2: error: expected '}' at end of input
   66 | }
      |  ^
a.cc:42:12: note: to match this '{'
   42 | int main() {
      |            ^
Language: C++

#include <bits/stdc++.h>
#define FI first
#define SE second
#define EPS 1e-9
#define ALL(a) a.begin(),a.end()
#define SZ(a) int((a).size())
#define MS(s, n) memset(s, n, sizeof(s))
#define FOR(i,a,b) for (int i = (a); i <= (b); i++)
#define FORE(i,a,b) for (int i = (a); i >= (b); i--)
#define FORALL(it, a) for (__typeof((a).begin()) it = (a).begin(); it != (a).end(); it++)
#define WHATIS(x) cout << #x << " is " << x << endl;
#define ERROR(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it, args); }
//__builtin_ffs(x) return 1 + index of least significant 1-bit of x
//__builtin_clz(x) return number of leading zeros of x
//__builtin_ctz(x) return number of trailing zeros of x

using namespace std;
using ll = long long;
using ld = double;
typedef pair<int, int> II;
typedef pair<ll, II> III;
typedef complex<ld> cd;
typedef vector<cd> vcd;

void err(istream_iterator<string> it) {}
template<typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
    cout << *it << " = " << a << endl;
    err(++it, args...);
}

const ll MODBASE = 1000000007LL;
const int MAXN = 400010;
const int MAXM = 100010;
const int MAXK = 510;
const int MAXQ = 200010;

int n;
string s, pre;

int main() {
    ios::sync_with_stdio(0);
    cin.tie(nullptr);
    cin >> n;
  FOR(i,1,n) {
    cin >> s;
    if (i == 1) {
   		ma[s];
	    pre = s;
    }
    else {
      if (ma.count(s)) {
        cout << "No";
        return 0;
      }
      if (s[0] != pre[SZ(pre)-1]) {
        cout << "No";
        return 0;
      }
      ma[s];
      pre = s;
    }
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:48:17: error: 'ma' was not declared in this scope; did you mean 'fma'?
   48 |                 ma[s];
      |                 ^~
      |                 fma
a.cc:52:11: error: 'ma' was not declared in this scope; did you mean 'fma'?
   52 |       if (ma.count(s)) {
      |           ^~
      |           fma
a.cc:60:7: error: 'ma' was not declared in this scope; did you mean 'fma'?
   60 |       ma[s];
      |       ^~
      |       fma
a.cc:64:2: error: expected '}' at end of input
   64 | }
      |  ^
a.cc:41:12: note: to match this '{'
   41 | int main() {
      |            ^
Language: C++

​#include<iostream>
#include<cstring>
using namespace std ;

int main()
{
  int N ;
  cin>>N ;
  char W[N][10] ;
  for(int i=0;i<N;i++) cin>>W[i] ;
  for(int i=0;i<N;i++) cout<<W[i] ;
  
  for(int i=0;i<N-1;i++){
    for(int j=i+1;j<N;j++){
      if(strcmp(W[i],W[j])==0){
        cout<<"No"<<endl ;
        return 0 ;
      }
    }
    if(W[i][strlen(W[i])-1]!= W[i+1][0]){
        cout<<"No"<<endl ;
        return 0 ;
    }
    
  }
  
  cout<<"Yes"<<endl ;
  
  return 0 ;
}

Compiler output:
a.cc:1:1: error: stray '#' in program
    1 | ​#include<iostream>
      | ^
a.cc:1:1: error: '\U0000200b' does not name a type
    1 | ​#include<iostream>
      |  
a.cc: In function 'int main()':
a.cc:8:3: error: 'cin' was not declared in this scope
    8 |   cin>>N ;
      |   ^~~
a.cc:3:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
    2 | #include<cstring>
  +++ |+#include <iostream>
    3 | using namespace std ;
a.cc:11:24: error: 'cout' was not declared in this scope
   11 |   for(int i=0;i<N;i++) cout<<W[i] ;
      |                        ^~~~
a.cc:11:24: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:16:9: error: 'cout' was not declared in this scope
   16 |         cout<<"No"<<endl ;
      |         ^~~~
a.cc:16:9: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:16:21: error: 'endl' was not declared in this scope
   16 |         cout<<"No"<<endl ;
      |                     ^~~~
a.cc:3:1: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
    2 | #include<cstring>
  +++ |+#include <ostream>
    3 | using namespace std ;
a.cc:21:9: error: 'cout' was not declared in this scope
   21 |         cout<<"No"<<endl ;
      |         ^~~~
a.cc:21:9: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:21:21: error: 'endl' was not declared in this scope
   21 |         cout<<"No"<<endl ;
      |                     ^~~~
a.cc:21:21: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
a.cc:27:3: error: 'cout' was not declared in this scope
   27 |   cout<<"Yes"<<endl ;
      |   ^~~~
a.cc:27:3: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:27:16: error: 'endl' was not declared in this scope
   27 |   cout<<"Yes"<<endl ;
      |                ^~~~
a.cc:27:16: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
Language: C++

#include <iostream>
#include <vector>
#include <string>

using namespace std;

bool solve(const vector<string>& W){
    const in n = W.size();
    //condition 1
    for(int i = 0; i < n-1; ++i){
        if(W[i].back() != W[i+1].front()){
            return false;
        }
    }

    //condition 2
    for(int i = 0; i < n; ++i){
        for(int j = i+1; j < n; ++j){
            if(W[i] == W[j]){
                return false;
            }
        }
    }
    return true;
}

vector<string> input() {
    int n; cin >> n;
    vector<string> W(n);
    for(int i = 0; i < n; ++i){
        cin >> W[i];
    }
    return W;
}

int main(){
    const vector<string> W = input();
    if(solve(W)){
        cout << "Yes" << endl;
    }
    else{
        cout << "No" << endl;
    }
}


Compiler output:
a.cc: In function 'bool solve(const std::vector<std::__cxx11::basic_string<char> >&)':
a.cc:8:11: error: 'in' does not name a type; did you mean 'int'?
    8 |     const in n = W.size();
      |           ^~
      |           int
a.cc:10:24: error: 'n' was not declared in this scope
   10 |     for(int i = 0; i < n-1; ++i){
      |                        ^
a.cc:17:24: error: 'n' was not declared in this scope
   17 |     for(int i = 0; i < n; ++i){
      |                        ^
Language: C

#include<stdio.h>
#include<string.h>
#include<stdbool.h>

int main(void){

  int length = 0;
  bool judge = true;

  int N;
  scanf("%d", &N);

  char W[100][11];
  for(int i = 0 ; i < N ; i++){
    scanf("%s",W[i]);
  }

  
  for(int i = 0 ; i < N - 1 ; i++){
    length = strlen(W[i]);
    if(W[i][length - 1] != W[i + 1][0])   judge = false;
    }
  }

  for(int i = 1 ; i < N ; i++){
    for(int j = 0 ; j < i ; j++){
      if(strcmp(&W[i],&W[j]) == 0){
			judge = false;
			break;
      }
    }
    
    if(judge == false)   break;

  }


  if(judge)     puts("Yes");
  else          puts("No");

  return 0;
}

Compiler output:
main.c:25:3: error: expected identifier or '(' before 'for'
   25 |   for(int i = 1 ; i < N ; i++){
      |   ^~~
main.c:25:21: error: expected '=', ',', ';', 'asm' or '__attribute__' before '<' token
   25 |   for(int i = 1 ; i < N ; i++){
      |                     ^
main.c:25:28: error: expected '=', ',', ';', 'asm' or '__attribute__' before '++' token
   25 |   for(int i = 1 ; i < N ; i++){
      |                            ^~
main.c:38:3: error: expected identifier or '(' before 'if'
   38 |   if(judge)     puts("Yes");
      |   ^~
main.c:39:3: error: expected identifier or '(' before 'else'
   39 |   else          puts("No");
      |   ^~~~
main.c:41:3: error: expected identifier or '(' before 'return'
   41 |   return 0;
      |   ^~~~~~
main.c:42:1: error: expected identifier or '(' before '}' token
   42 | }
      | ^
Language: C++

N = int(input())
W = [input() for _ in range(N)]

l = [W[0]]

for i in range(1, N):
    if W[i - 1][-1] == W[i][0] and W[i] not in l:
        l.append(W[i])
    else:
        print("No")
        exit()

print("Yes")


Compiler output:
a.cc:1:1: error: 'N' does not name a type
    1 | N = int(input())
      | ^
Language: Java

import java.util.*;
class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        List<String> w = new ArrayList<String>();
        boolean jud = false;
      
        for(int i = 0; i < n;i++){
            String word = sc.next();
            if(a.contains(word)){
                jud = false;
                break;
            }
            w.add(word);
            jud = true;            
        }

        if(jud == true){
            for(int i = 0;i < w.size();i++){
                String w1 = w.get(i);
                String w2 = w.get(i+1);
                char a = w1.charAt(w1.length()-1);
                char b = w2.charAt(0);
                if(a != b){
                    jud = false;
                    break;
                }
            }
        }

        if(jud == true){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
}

Compiler output:
Main.java:12: error: cannot find symbol
            if(a.contains(word)){
               ^
  symbol:   variable a
  location: class Main
1 error
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
  int n;
  string ans = "No";
  cin>>n;
  
  vector<string> w(n);
  for(int i=0;i<n;i++){
    cin>>w.at(i);
  }
  for(int i=0;i<n-1;i++){
    for(int j=0;j<n;j++){
      if(w.at(i).end == w.at(i+1).begin && w.at(i) != w.at(j) && i != j){
        ans = "Yes";
      }
    }
  }
  cout<<ans<<endl;
}
  
  
  
    

Compiler output:
a.cc: In function 'int main()':
a.cc:15:22: error: invalid operands of types '<unresolved overloaded function type>' and '<unresolved overloaded function type>' to binary 'operator=='
   15 |       if(w.at(i).end == w.at(i+1).begin && w.at(i) != w.at(j) && i != j){
      |          ~~~~~~~~~~~ ^~ ~~~~~~~~~~~~~~~
      |                  |                |
      |                  |                <unresolved overloaded function type>
      |                  <unresolved overloaded function type>
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  vector<string> W(N);
  vector<int> X(N);
  for(int i=0;i<N;i++){
    cin >> W[i];
    X[i] = W[i].size();
  }
  string ans;
  for(int i=0;i<N-1;i++){
    if(W[i].at(X[i])) != W[i+1].at(0)){
      cout << "No" << endl;
      return 0;
    }
  else{
    ans="Yes";
  }
  }
    cout << ans << endl;
}
    

Compiler output:
a.cc: In function 'int main()':
a.cc:14:23: error: expected primary-expression before '!=' token
   14 |     if(W[i].at(X[i])) != W[i+1].at(0)){
      |                       ^~
Language: C++

#include<iostream>
#include<vector>

using namespace std;

int main(){
  int N;
  cin >> N;
  vector<string> w(N);
  
  for(int i = 0; i < N; i++) cin >> w[i];
  int f = 0;
  for(int i = 0; i < N; i++){
    for(int j = 0; j < N; j++){
      if(i == j) continue;
      if(w[i] == w[j]) f = 1;
    }
  }
  
  for(int i = 1; i < N; i++){
    if(w[i-1][[w[i-1].length() - 1]] != w[i][[w[i].length() - 1]]) f = 1;
  }
  if(f) cout << "No";
  else cout << "Yes";
}


Compiler output:
a.cc: In function 'int main()':
a.cc:21:14: error: two consecutive '[' shall only introduce an attribute before '[' token
   21 |     if(w[i-1][[w[i-1].length() - 1]] != w[i][[w[i].length() - 1]]) f = 1;
      |              ^
a.cc:21:14: error: expected ')' before '[' token
   21 |     if(w[i-1][[w[i-1].length() - 1]] != w[i][[w[i].length() - 1]]) f = 1;
      |       ~      ^
      |              )
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  int n;
  cin>>n;
  vector<string> v(n);
  for(int i=0;i<n;i++){
    cin>>v[i];
  }
  for(int i=0;i<n-1;i++){
    if(v[i].back()!=v[i+1].front()){
      cout<<"NO";
      exit(0);
    }
  }
    for(int i=0;i<n;i++){
      for(int j=i+1;j<n;j++){
        if(v[i]==v[j]){
          cout<<"NO";
      exit(0);
    }
  }
     cout<<"Yes";
    }

Compiler output:
a.cc: In function 'int main()':
a.cc:24:6: error: expected '}' at end of input
   24 |     }
      |      ^
a.cc:3:11: note: to match this '{'
    3 | int main(){
      |           ^
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
  int N;
  cin>>N;
  
  string W[N];
  for(int i=0;i<N;i++){
    cin>>W[i];
  }
  
  bool ans=true;
  for(int i=0;i<N-1;i++){
    if(W[i][W[1].length()-1]!==W[i+1][0]){
      ans=false;
    }
  }
  for(int i=0;i<N;i++){
    for(int j=0;j<N;j++){
      if(W[i]==W[j]){
        ans=false;
      }
    }
  }
  
  if(ans){
    cout<<"Yes"<<endl;
  }
  else{cout<<"No"<<endl;
      }
}
  
  


Compiler output:
a.cc: In function 'int main()':
a.cc:15:31: error: expected primary-expression before '=' token
   15 |     if(W[i][W[1].length()-1]!==W[i+1][0]){
      |                               ^
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
  int N;
  cin>>N;
  
  string W[N];
  for(int i=0;i<N;i++>){
    cin>>W[i];
  }
  
  bool ans=true;
  for(int i=0;i<N-1;i++>){
    if(W[i][W[1].length()-1]!=W[i+1][0]){
      ans=false;
    }
  }
  for(int i=0;i<N;i++>){
    for(int j=0;j<N;j++>){
      if(W[i]==W[j]){
        ans=false;
      }
    }
  }
  
  if(ans){
    cout<<"Yes"<<endl;
  }
  else{cout<<"No"<<endl;
      }
}
  
  

Compiler output:
a.cc: In function 'int main()':
a.cc:9:23: error: expected primary-expression before ')' token
    9 |   for(int i=0;i<N;i++>){
      |                       ^
a.cc:14:25: error: expected primary-expression before ')' token
   14 |   for(int i=0;i<N-1;i++>){
      |                         ^
a.cc:19:23: error: expected primary-expression before ')' token
   19 |   for(int i=0;i<N;i++>){
      |                       ^
a.cc:20:25: error: expected primary-expression before ')' token
   20 |     for(int j=0;j<N;j++>){
      |                         ^
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  int n;
  vector<string> s(n);
  for(int i = 0; i<n ; i++){
    cin >> s.at(i);
  }
  int count =0;
  bool y = true;
  
  for(int i = 0 ; i<n; i++){
    for(int j = 0; j<n ; ++){
      if(s.at(i) == s.at(j)){
        count++;
      }
    }
  }
  if(count > n){
    cout << "No" << endl;
  }
  else {
    for(int i = 0 ; i<n-1; i++){
      x = s.at(i).size();
      if(s.at(i).at(x-1) != s.at(i++).at(0)){
        cout << "No" << endl;
        y = false;
        break;
      }
    }
    if(y){
      cout << "Yes" << endl;
    }
  }
}



Compiler output:
a.cc: In function 'int main()':
a.cc:14:28: error: expected primary-expression before ')' token
   14 |     for(int j = 0; j<n ; ++){
      |                            ^
a.cc:25:7: error: 'x' was not declared in this scope
   25 |       x = s.at(i).size();
      |       ^