Language: C++

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <tuple>
#include <utility>
#include <vector>
#define ll long long
#define double long double
#define itn int
#define endl '\n'
#define co(ans) cout<<ans<<endl
#define COYE cout<<"YES"<<endl
#define COYe cout<<"Yes"<<endl
#define COye cout<<"yes"<<endl
#define CONO cout<<"NO"<<endl
#define CONo cout<<"No"<<endl
#define COno cout<<"no"<<endl
#define FORE(i,a) for(auto &i:a)
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define FFOR(i,a,b) for(int i=(a);i<=(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define RREP(i,n)  FFOR(i,1,n)
#define PB push_back
#define MP make_pair
#define ALL(V) (V).begin(),(V).end()
#define SORT(V) sort((V).begin(),(V).end())
#define REVERSE(V) reverse((V).begin(),(V).end())
#define EACH(V,i) for(typeof((V).begin()) i=(V).begin();i!=(V).end();++i)
#define INF ((1LL<<62)-(1LL<<31))
#define EPS 1e-10
#define PI 3.141592653589793238
#define MOD 1000000007
#define MAX 5100000
using namespace std;
using Graph=vector<vector<int>>;
inline int toInt(string s){int v;istringstream sin(s);sin>>v;return v;}
template<class T>inline string toString(T x){ostringstream sout;sout<<x;return sout.str();}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return 1;}return 0;}
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
const int dx[4]={0,1,0,-1},dy[4]={1,0,-1,0};
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
ll lcm(ll a,ll b){return a/gcd(a,b)*b;}

int N;
int A[101010];
int B[101010];
map<int,int> M[2];
map<int,int> T;
int is[101010];

template<int um> class UF {
	public:
	vector<int> par,rank;
	UF() {rank=vector<int>(um,0); for(int i=0;i<um;i++) par.push_back(i);}
	int operator[](int x) {return (par[x]==x)?(x):(par[x] = operator[](par[x]));}
	int operator()(int x,int y) {
		if((x=operator[](x))==(y=operator[](y))) return x;
		if(rank[x]>rank[y]) return par[x]=y;
		rank[x]+=rank[x]==rank[y]; return par[y]=x;
	}
};
UF<500000> uf;

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>N;
	
	FOR(i,N) cin>>A[i];
	FOR(i,N) cin>>B[i];
	int cur[2]={};
	FOR(i,N) {
		cur[0] ^= A[i];
		cur[1] ^= B[i];
		M[0][A[i]]++;
		M[1][B[i]]++;
		T[A[i]]=T[B[i]]=0;
	}
	M[0][cur[0]]++;
	M[1][cur[1]]++;
	if(M[0]!=M[1]) return _P("-1\n");
	T[cur[0]]=T[cur[1]]=0;
	x=0;
	FORR(r,T) r.second=x++;
	
	is[T[cur[0]]]=is[T[cur[1]]]=1;
	uf(T[cur[0]],T[cur[1]]);
	int ns=0;
	FOR(i,N) if(A[i]!=B[i]) {
		ns++;
		is[T[A[i]]]=is[T[B[i]]]=1;
		uf(T[A[i]],T[B[i]]);
	}
	
	FOR(i,T.size()) if(is[i]&&uf[i]==i) ns++;
	ns--;
	cout<<ns<<endl;
}

Compiler output:
a.cc:94:16: error: macro "FOR" requires 3 arguments, but only 2 given
   94 |         FOR(i,N) cin>>A[i];
      |                ^
a.cc:39:9: note: macro "FOR" defined here
   39 | #define FOR(i,a,b) for(int i=(a);i<(b);++i)
      |         ^~~
a.cc:95:16: error: macro "FOR" requires 3 arguments, but only 2 given
   95 |         FOR(i,N) cin>>B[i];
      |                ^
a.cc:39:9: note: macro "FOR" defined here
   39 | #define FOR(i,a,b) for(int i=(a);i<(b);++i)
      |         ^~~
a.cc:97:16: error: macro "FOR" requires 3 arguments, but only 2 given
   97 |         FOR(i,N) {
      |                ^
a.cc:39:9: note: macro "FOR" defined here
   39 | #define FOR(i,a,b) for(int i=(a);i<(b);++i)
      |         ^~~
a.cc:114:16: error: macro "FOR" requires 3 arguments, but only 2 given
  114 |         FOR(i,N) if(A[i]!=B[i]) {
      |                ^
a.cc:39:9: note: macro "FOR" defined here
   39 | #define FOR(i,a,b) for(int i=(a);i<(b);++i)
      |         ^~~
a.cc:120:23: error: macro "FOR" requires 3 arguments, but only 2 given
  120 |         FOR(i,T.size()) if(is[i]&&uf[i]==i) ns++;
      |                       ^
a.cc:39:9: note: macro "FOR" defined here
   39 | #define FOR(i,a,b) for(int i=(a);i<(b);++i)
      |         ^~~
a.cc: In function 'void solve()':
a.cc:94:9: error: 'FOR' was not declared in this scope
   94 |         FOR(i,N) cin>>A[i];
      |         ^~~
a.cc:95:12: error: expected ';' before 'cin'
   95 |         FOR(i,N) cin>>B[i];
      |            ^     ~~~
      |            ;
a.cc:97:12: error: expected ';' before '{' token
   97 |         FOR(i,N) {
      |            ^     ~
      |            ;
a.cc:106:31: error: '_P' was not declared in this scope; did you mean 'MP'?
  106 |         if(M[0]!=M[1]) return _P("-1\n");
      |                               ^~
      |                               MP
a.cc:109:9: error: 'FORR' was not declared in this scope; did you mean 'FOR'?
  109 |         FORR(r,T) r.second=x++;
      |         ^~~~
      |         FOR
a.cc:114:12: error: expected ';' before 'if'
  114 |         FOR(i,N) if(A[i]!=B[i]) {
      |            ^     ~~
      |            ;
a.cc:120:12: error: expected ';' before 'if'
  120 |         FOR(i,T.size()) if(is[i]&&uf[i]==i) ns++;
      |            ^            ~~
      |            ;