Language: C++

#include <bits/stdc++.h>

using namespace std;
using ll = long long;
// #define int ll
using PII = pair<ll, ll>;

#define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(x) x.begin(), x.end()

template<typename T> T &chmin(T &a, const T &b) { return a = min(a, b); }
template<typename T> T &chmax(T &a, const T &b) { return a = max(a, b); }
template<typename T> bool IN(T a, T b, T x) { return a<=x&&x<b; }
template<typename T> T ceil(T a, T b) { return a/b + !!(a%b); }

template<typename T> vector<T> make_v(size_t a) { return vector<T>(a); }
template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts) {
    return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}
template<typename T,typename V> typename enable_if<is_class<T>::value==0>::type
fill_v(T &t, const V &v) { t=v; }
template<typename T,typename V> typename enable_if<is_class<T>::value!=0>::type
fill_v(T &t, const V &v ) { for(auto &e:t) fill_v(e,v); }

template<class S,class T>
ostream &operator <<(ostream& out,const pair<S,T>& a) {
    out<<'('<<a.first<<','<<a.second<<')'; return out;
}
template<class T>
ostream &operator <<(ostream& out,const vector<T>& a){
    out<<'[';
    for(const T &i: a) out<<i<<',';
    out<<']';
    return out;
}
template<class T>
ostream &operator <<(ostream& out, const set<T>& a) {
    out<<'{';
    for(const T &i: a) out<<i<<',';
    out<<'}';
    return out;
}
template<class T, class S>
ostream &operator <<(ostream& out, const map<T,S>& a) {
    out<<'{';
    for(auto &i: a) out<<i<<',';
    out<<'}';
    return out;
}

int dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0}; // DRUL
const int INF = 1<<30;
const ll LLINF = 1LL<<60;
const ll MOD = 1000000007;

signed main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    bool flag = true;
    REP(i, n) if(a[i] != 0) flag = false;
    if(flag) {
        cout << "Yes" << endl;
        return 0;
    }

    sort(ALL(a));
    flag = true;
    REP(i, n/3) if(a[i] != a[0]) flag = false;
    FOR(i, n/3, n*2/3) if(a[i] != a[n/3]) flag = false;
    FOR(i, n*2/3, n) if(a[i] != a[n*2/3]) flag = false;
    if((a[0]^a[n/3]) != a[n-1]) flag = false;

    if(flag) {
        cout << "Yes" << endl;
        return 0;
    }

    cout << "No" << endl;

    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:64:12: error: 'n' was not declared in this scope
   64 |     REP(i, n) if(a[i] != 0) flag = false;
      |            ^
a.cc:8:49: note: in definition of macro 'FOR'
    8 | #define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
      |                                                 ^
a.cc:64:5: note: in expansion of macro 'REP'
   64 |     REP(i, n) if(a[i] != 0) flag = false;
      |     ^~~
a.cc:64:18: error: 'a' was not declared in this scope
   64 |     REP(i, n) if(a[i] != 0) flag = false;
      |                  ^
a.cc:70:14: error: 'a' was not declared in this scope
   70 |     sort(ALL(a));
      |              ^
a.cc:10:16: note: in definition of macro 'ALL'
   10 | #define ALL(x) x.begin(), x.end()
      |                ^
a.cc:72:12: error: 'n' was not declared in this scope
   72 |     REP(i, n/3) if(a[i] != a[0]) flag = false;
      |            ^
a.cc:8:49: note: in definition of macro 'FOR'
    8 | #define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
      |                                                 ^
a.cc:72:5: note: in expansion of macro 'REP'
   72 |     REP(i, n/3) if(a[i] != a[0]) flag = false;
      |     ^~~
a.cc:73:12: error: 'n' was not declared in this scope
   73 |     FOR(i, n/3, n*2/3) if(a[i] != a[n/3]) flag = false;
      |            ^
a.cc:8:38: note: in definition of macro 'FOR'
    8 | #define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
      |                                      ^
a.cc:74:12: error: 'n' was not declared in this scope
   74 |     FOR(i, n*2/3, n) if(a[i] != a[n*2/3]) flag = false;
      |            ^
a.cc:8:38: note: in definition of macro 'FOR'
    8 | #define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
      |                                      ^
a.cc:75:16: error: 'n' was not declared in this scope; did you mean 'yn'?
   75 |     if((a[0]^a[n/3]) != a[n-1]) flag = false;
      |                ^
      |                yn