Language: C++

#include <bits/stdc++.h>
#include <cstdio>
#include <vector>
#include <iostream>
#include <utility>

#define fir first
#define sec second
#define get(n) scanf("%d",&n);
#define gets(s) string s;cin >> (s);
#define All(s) (c).begin(), (c).end()
#define chmin(x, y) x = min(x, y);
#define chmax(x, y) x = max(x, y);
#define rep(i, j) for (int (i)=0;(i)<(j);(i)++)
#define repk(i, j, k) for(int (i)=(j);(i)<(k);(i)++)
#define dump(x)  cout << #x << " = " << (x) << endl;
#define debug(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
using namespace std;
typedef long long int ll;
const ll INF = 10241024;

int N;
vector<pair<int, int> > cor;

void input() {
    cin >> N;
    rep(i, N){
        int a,b;cin >> a >> b;
        cor[i].fir = a;
        cor[i].sec = b;
    }
}

void solve() {
    vector<pair<int, string> ans(N);
    bool ok = true;
    int j = 0;

    for (int i=1;i<=N;i++){
        int a,b;
        a = cor[i].fir - cor[i-1].fir;
        b = cor[i],sec - cor[i-1].sec;
        if(a != 0 && b != 00){
            cout << -1 << endl;
            ok = false;
            break;
        }
        if(b == 0){
            ans[j].fir = a;
            if(a>0){
                ans[j].sec = "R";
            }else {
                ans[j].sec = "L"; 
            }
        }else {
            ans[j].fir = b;
            if(b > 0){
                ans[j].sec = "U";
            }else {
                ans[j].sec = "D";
            }
        }
    }

    if(!ok) {
        rep(int i=0;i<=j;i++){
            cout << ans[i].fir << " " ;
        }
        rep(int i=0;i<=j;i++){
            cout << ans[i].sec << endl;
        }
    }
}

int main () {
    solve();
    return 0;
}

Compiler output:
a.cc:66:29: error: macro "rep" requires 2 arguments, but only 1 given
   66 |         rep(int i=0;i<=j;i++){
      |                             ^
a.cc:14:9: note: macro "rep" defined here
   14 | #define rep(i, j) for (int (i)=0;(i)<(j);(i)++)
      |         ^~~
a.cc:69:29: error: macro "rep" requires 2 arguments, but only 1 given
   69 |         rep(int i=0;i<=j;i++){
      |                             ^
a.cc:14:9: note: macro "rep" defined here
   14 | #define rep(i, j) for (int (i)=0;(i)<(j);(i)++)
      |         ^~~
a.cc: In function 'void solve()':
a.cc:35:35: error: template argument 1 is invalid
   35 |     vector<pair<int, string> ans(N);
      |                                   ^
a.cc:35:35: error: template argument 2 is invalid
a.cc:42:18: error: cannot convert '__gnu_cxx::__alloc_traits<std::allocator<std::pair<int, int> >, std::pair<int, int> >::value_type' {aka 'std::pair<int, int>'} to 'int' in assignment
   42 |         b = cor[i],sec - cor[i-1].sec;
      |                  ^
a.cc:8:13: error: 'second' was not declared in this scope
    8 | #define sec second
      |             ^~~~~~
a.cc:42:20: note: in expansion of macro 'sec'
   42 |         b = cor[i],sec - cor[i-1].sec;
      |                    ^~~
a.cc:49:13: error: 'ans' was not declared in this scope; did you mean 'abs'?
   49 |             ans[j].fir = a;
      |             ^~~
      |             abs
a.cc:56:13: error: 'ans' was not declared in this scope; did you mean 'abs'?
   56 |             ans[j].fir = b;
      |             ^~~
      |             abs
a.cc:66:9: error: 'rep' was not declared in this scope
   66 |         rep(int i=0;i<=j;i++){
      |         ^~~
a.cc:69:12: error: expected ';' before '{' token
   69 |         rep(int i=0;i<=j;i++){
      |            ^                 ~
      |            ;