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

#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define coR() cout << 'R'
#define coL() cout << 'L'
#define coU() cout << 'U'
#define coD() cout << 'D'
using namespace std;
int main(){
  int sx,sy,tx,ty;
  cin >> sx >> sy >> tx >> ty;
  int distx = tx - sx;
  int disty = tx - sx;
  
  rep(i,distx){ coR(); }
  rep(i,disty){ coU(); }
  rep(i,distx){ coL(); }
  rep(i,disty+1){ coD(); }
  rep(i,distx+1){ coR(); }
  rep(i,disty+1){ coU(); }
  coL();
  coU();
  rep(i,distx+1){ coL(); }
  rep(i,disty+1){ coD(); }
  coR();


Compiler output:
a.cc: In function 'int main()':
a.cc:24:9: error: expected '}' at end of input
   24 |   coR();
      |         ^
a.cc:8:11: note: to match this '{'
    8 | int main(){
      |           ^
Language: C++

#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define co('a') cout << 'a' << endl
using namespace std;
int main(){
  int sx,sy,tx,ty;
  cin >> sx >> sy >> tx >> ty;
  int distx = tx - sx;
  int disty = tx - sx;
  
  rep(i,distx){ co(R); }
  rep(i,disty){ co(U); }
  rep(i,distx){ co(L); }
  rep(i,disty+1){ co(D); }
  rep(i,distx+1){ co(R); }
  rep(i,disty+1){ co(U); }
  co(L);
  co(U);
  rep(i,distx+1){ co(L); }
  rep(i,disty+1){ co(D); }
  co(R);
}

Compiler output:
a.cc:3:12: error: expected parameter name, found "'a'"
    3 | #define co('a') cout << 'a' << endl
      |            ^~~
a.cc: In function 'int main()':
a.cc:11:20: error: 'R' was not declared in this scope
   11 |   rep(i,distx){ co(R); }
      |                    ^
a.cc:11:17: error: 'co' was not declared in this scope; did you mean 'cos'?
   11 |   rep(i,distx){ co(R); }
      |                 ^~
      |                 cos
a.cc:12:20: error: 'U' was not declared in this scope
   12 |   rep(i,disty){ co(U); }
      |                    ^
a.cc:12:17: error: 'co' was not declared in this scope; did you mean 'cos'?
   12 |   rep(i,disty){ co(U); }
      |                 ^~
      |                 cos
a.cc:13:20: error: 'L' was not declared in this scope
   13 |   rep(i,distx){ co(L); }
      |                    ^
a.cc:13:17: error: 'co' was not declared in this scope; did you mean 'cos'?
   13 |   rep(i,distx){ co(L); }
      |                 ^~
      |                 cos
a.cc:14:22: error: 'D' was not declared in this scope
   14 |   rep(i,disty+1){ co(D); }
      |                      ^
a.cc:14:19: error: 'co' was not declared in this scope; did you mean 'cos'?
   14 |   rep(i,disty+1){ co(D); }
      |                   ^~
      |                   cos
a.cc:15:22: error: 'R' was not declared in this scope
   15 |   rep(i,distx+1){ co(R); }
      |                      ^
a.cc:15:19: error: 'co' was not declared in this scope; did you mean 'cos'?
   15 |   rep(i,distx+1){ co(R); }
      |                   ^~
      |                   cos
a.cc:16:22: error: 'U' was not declared in this scope
   16 |   rep(i,disty+1){ co(U); }
      |                      ^
a.cc:16:19: error: 'co' was not declared in this scope; did you mean 'cos'?
   16 |   rep(i,disty+1){ co(U); }
      |                   ^~
      |                   cos
a.cc:17:6: error: 'L' was not declared in this scope
   17 |   co(L);
      |      ^
a.cc:17:3: error: 'co' was not declared in this scope; did you mean 'cos'?
   17 |   co(L);
      |   ^~
      |   cos
a.cc:18:6: error: 'U' was not declared in this scope
   18 |   co(U);
      |      ^
a.cc:20:22: error: 'D' was not declared in this scope
   20 |   rep(i,disty+1){ co(D); }
      |                      ^
a.cc:21:6: error: 'R' was not declared in this scope
   21 |   co(R);
      |      ^
Language: C++

#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define co(a) cout << a << endl
using namespace std;
int main(){
  int sx,sy,tx,ty;
  cin >> sx >> sy >> tx >> ty;
  distx = tx - sx;
  disty = tx - sx;
  
  rep(i,distx){ co(R); }
  rep(i,disty){ co(U); }
  rep(i,distx){ co(L); }
  rep(i,disty+1){ co(D); }
  rep(i,distx+1){ co(R); }
  rep(i,disty+1){ co(U); }
  co(L);
  co(U);
  rep(i,distx+1){ co(L); }
  rep(i,disty+1){ co(D); }
  co(R);
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:3: error: 'distx' was not declared in this scope
    8 |   distx = tx - sx;
      |   ^~~~~
a.cc:9:3: error: 'disty' was not declared in this scope
    9 |   disty = tx - sx;
      |   ^~~~~
a.cc:11:20: error: 'R' was not declared in this scope
   11 |   rep(i,distx){ co(R); }
      |                    ^
a.cc:3:23: note: in definition of macro 'co'
    3 | #define co(a) cout << a << endl
      |                       ^
a.cc:12:20: error: 'U' was not declared in this scope
   12 |   rep(i,disty){ co(U); }
      |                    ^
a.cc:3:23: note: in definition of macro 'co'
    3 | #define co(a) cout << a << endl
      |                       ^
a.cc:13:20: error: 'L' was not declared in this scope
   13 |   rep(i,distx){ co(L); }
      |                    ^
a.cc:3:23: note: in definition of macro 'co'
    3 | #define co(a) cout << a << endl
      |                       ^
a.cc:14:22: error: 'D' was not declared in this scope
   14 |   rep(i,disty+1){ co(D); }
      |                      ^
a.cc:3:23: note: in definition of macro 'co'
    3 | #define co(a) cout << a << endl
      |                       ^
a.cc:15:22: error: 'R' was not declared in this scope
   15 |   rep(i,distx+1){ co(R); }
      |                      ^
a.cc:3:23: note: in definition of macro 'co'
    3 | #define co(a) cout << a << endl
      |                       ^
a.cc:16:22: error: 'U' was not declared in this scope
   16 |   rep(i,disty+1){ co(U); }
      |                      ^
a.cc:3:23: note: in definition of macro 'co'
    3 | #define co(a) cout << a << endl
      |                       ^
a.cc:17:6: error: 'L' was not declared in this scope
   17 |   co(L);
      |      ^
a.cc:3:23: note: in definition of macro 'co'
    3 | #define co(a) cout << a << endl
      |                       ^
a.cc:18:6: error: 'U' was not declared in this scope
   18 |   co(U);
      |      ^
a.cc:3:23: note: in definition of macro 'co'
    3 | #define co(a) cout << a << endl
      |                       ^
a.cc:20:22: error: 'D' was not declared in this scope
   20 |   rep(i,disty+1){ co(D); }
      |                      ^
a.cc:3:23: note: in definition of macro 'co'
    3 | #define co(a) cout << a << endl
      |                       ^
a.cc:21:6: error: 'R' was not declared in this scope
   21 |   co(R);
      |      ^
a.cc:3:23: note: in definition of macro 'co'
    3 | #define co(a) cout << a << endl
      |                       ^
Language: C++

#include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < n; ++i)
#define rrep(i, n) for(int i = n-1; i >= 0; --i)
#define fi first
#define se second
using namespace std;
using lint = long long;
using uint = unsigned int;
using ulint = unsigned long long;
using ldouble = long double;
using pii = pair<int, int>;
using pli = pair<lint, lint>;
using pdd = pair<double, double>;
using pld = pair<ldouble, ldouble>;
using v1i = vector<int>;
using v1li = vector<lint>;
using v2i = vector<vector<int>>;
using v2li = vector<vector<lint>>;
using v3i = vector<vector<vector<int>>>;
using v3li = vector<vector<vector<lint>>>;
using v1b = vector<bool>;
using v2b = vector<vector<bool>>;
using v3b = vector<vector<vector<bool>>>;
using v1c = vector<char>;
using v2c = vector<vector<char>>;
using v3c = vector<vector<vector<char>>>;
constexpr lint mod1 = 1e9+7;
constexpr lint mod2 = 998244353;

int main() {
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  string t = "";
  rep(i, c-a) t += 'R';
  rep(i, d-b) t += 'U';
  rep(i, c-a) t += 'L';
  rep(i, d-b) t += 'D';
  t += 'D';
  rep(i, c-a+1) t += 'R';
  rep(i, d-b+1) t += 'U';
  t += 'L';
  t += 'U';
  rep(i, c-a+1) t += 'L';
  rep(i, d-b+1) t += 'D';
  t += 'R'
  cout << t << endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:45:11: error: expected ';' before 'cout'
   45 |   t += 'R'
      |           ^
      |           ;
   46 |   cout << t << endl;
      |   ~~~~
Language: C++

#define _GLIBCXX_DEBUG
#include<bits/stdc++.h>
#define rep(i,n) for (int i = 0;i < (n);i++)
#define all(v) v.begin(),v.end()
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
using vl = vector<ll>;
using vvl = vector<vl>;


int main(){
  ll sx,sy,tx,ty; cin >> sx >> sy >> tx >> ty;
  ll dx = tx-sx; ll dy = ty-sy;
  
  cout << string(dx,'R') << string(dy,'U') << string(dx,'L') 
       << string(dy,'D') << 'D' << string(dx+1,'R') << 
       << string(dy+1,'U') << 'L' << 'U' << string(dx+1,'L')
       << string(dy+1,'D') << 'R' << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:18:8: error: expected primary-expression before '<<' token
   18 |        << string(dy+1,'U') << 'L' << 'U' << string(dx+1,'L')
      |        ^~
Language: C++

#include<bits/stdc++.h>
#include<iomanip>
using namespace std;
typedef long long ll;
typedef long  l;
typedef pair<int,int> P;
#define rep(i,n) for(int i=0;i<n;i++)
#define fs first
#define sc second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define ALL(A) A.begin(),A.end()
const double PI=3.141592653589;
const int INF=1000000007;
const ll LMAX=1000000000000001;
ll gcd(ll a,ll b){if(a<b)swap(a,b);ll c=a%b;while(c!=0){a=b;b=c;c=a%b;}return b;}
ll lcm(ll a,ll b){return a*b/gcd(a,b);}
int dx[]={-1,0,1,0};
int dy[]={0,1,0,-1};

int main(){
  int sx,sy,tx,ty; cin>>sx>>sy>>tx>>ty;
  rep(i,tx-sx) cout<<"R";
  rep(i,ty-sy) cout<<"U";
  rep(i,tx-sx) cout<<"L";
  rep(i,ty-sy) cout<<"D";
  cout<<"D"
  rep(i,tx-sx+1) cout<<"R";
  rep(i,ty-sy+1) cout<<"U";
  cout<<"LU";
  rep(i,tx-sx+1) cout<<"L";
  rep(i,ty-sy+1) cout<<"D";
  cout<<"R"<<endl;


  return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:28:12: error: expected ';' before 'for'
   28 |   cout<<"D"
      |            ^
      |            ;
a.cc:29:7: error: 'i' was not declared in this scope
   29 |   rep(i,tx-sx+1) cout<<"R";
      |       ^
a.cc:7:30: note: in definition of macro 'rep'
    7 | #define rep(i,n) for(int i=0;i<n;i++)
      |                              ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
using int64 = long long;
#define int int64
#define rep(i, n) for(int i=0; i<n; i++)
#define FOR(i, a, b) for(int i=a; i<b; i++)
#define SORT(x) sort(x.begin(), x.end())
#define GSORT(x) sort(x.begin(), x.end(), greater<int>())
#define mk make_pair
#define fi first
#define se second
#define pb push_back
#define ALL(x) x.begin(), x.end()
#define V(T) vector<T>
typedef pair<int, int> P;
typedef pair<P, P> PP;
typedef vector<int> vi;
typedef vector<vi> vvi;
int max(int a, int b) {if(b>a) return b; else return a;}
int min(int a, int b) {if(b<a) return b; else return a;}

signed main() {
    int sx, sy, tx, ty;
    cin >> sx >> sy >> tx >> ty;

    //int x=sx, y=sy;
    //cout << sx << " " << sy << endl;
    string res = "";
    rep(i, tx-sx) res += 'R';
    rep(i, ty-sy) res += 'U';
    rep(i, tx-sx) res += 'L';
    rep(i, ty-sy) res += 'D';
    res += 'D';
    rep(i, tx-sx+1) res += 'R';
    rep(i, ty-sy+1) res += 'U';
    res += "LU";
    rep(i, tx-sx+1) res += 'L';
    rep(i, ty-sy+1) res += 'D';
    res += 'R';

    rep(i, res.size()) {
        switch(res[i]) {
            case 'U':
                y++;
                break;
            
            case 'D':
                y--;
                break;

            case 'R':
                x++;
                break;

            case 'L':
                x--;
                break;
        }
    }

    //cout << x << " " << y << endl;

    cout << res << endl;
 
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:44:17: error: 'y' was not declared in this scope
   44 |                 y++;
      |                 ^
a.cc:52:17: error: 'x' was not declared in this scope
   52 |                 x++;
      |                 ^
Language: Java

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner scanner = new Scanner(System.in);
		int sx = scanner.nextInt();
		int sy = scanner.nextInt();
		int tx = scanner.nextInt();
		int ty = scanner.nextInt();
		scanner.close();
//		String result = "";
		List<String> result = new ArrayList<String>();
//		String rr = "";
		StringBuilder sb = new StringBuilder();
		sb.append("U");
		System.out.println(sb);
		// 1回目
		for(int i = 0; i < ty - sy; i++){
//			result += "U";
			sb.append("U")
		}
		for(int i = 0; i < tx - sx; i++){
//			result += "R";
			sb.append("R");
		}

		for(int i = 0; i < ty - sy; i++){
//			result += "D";
			sb.append("D");
		}
		for(int i = 0; i < tx - sx; i++){
//			result += "L";
			sb.append("L");
		}
		/// 2回目
//		result += "L";
		sb.append("L");
		for(int i = 0; i < ty - sy; i++){
//			result += "U";
			sb.append("U");
		}
//		result += "U";
		for(int i = 0; i < tx - sx; i++){
//			result += "R";
			sb.append("R");
		}
//		result += "RDR";
		sb.append("RDR");

		for(int i = 0; i < ty - sy; i++){
//			result += "D";
			sb.append("D");
		}
//		result += "D";
		for(int i = 0; i < tx - sx; i++){
//			result += "L";
			sb.append("L");
		}
//		result += "LU";
		sb.append("LU");

//		System.out.println(result);
		System.out.println(sb);

	}

}


Compiler output:
Main.java:24: error: ';' expected
			sb.append("U")
			              ^
1 error
Language: C++

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

int main(){
 int a,b,aa,bb; cin >> a >> b >> aa >> bb;
 int x = aa - a;
 int y = bb - b;
  
  int signx , signy = 0;0;
  if(x<0){
    signx = -1;
  }
  else{
    signx = 1;
  }
  
  if(y<0){
    signy = -1;
  }
  else{
    signy = 1
  }
  
  int countx,county = 0;0;
  while(x!=0){
    if(x<0){
      cout << 'R';
      x++;
    }
    else{
      cout << 'L';
      x--;
    }
    countx++;
  }
  while(y!=0){
    if(y<0){
      cout << 'U';
      y++;
    }
    else{
      cout << 'D';
      y--;
    }
    county++;
  }
  
  if(signx == 1){
    x += countx;
  }
  else{
    x -= countx;
  }
  
  if(signy == 1){
    y += county;
  }
  else{
    y -= county;
  }
  
  while(x!=0){
    if(x<0){
      cout << 'L';
      x++;
    }
    else{
      cout << 'R';
      x--;
    }
    countx++;
  }
  while(y!=0){
    if(y<0){
      cout << 'D';
      y++;
    }
    else{
      cout << 'U';
      y--;
    }
    county++;
  }
  
    
  if(signx == 1){
    x += countx;
  }
  else{
    x -= countx;
  }
  
  if(signy == 1){
    y += county;
  }
  else{
    y -= county;
  }
  
  if(signx == 1){
    cout << 'L';
  }
  else{
    cout << 'R';
  }
  if(signy == 1){
    cout << 'U';
  }
  else{
    cout << 'D';
  }
  
  while(x!=0){
    if(x<0){
      cout << 'R';
      x++;
    }
    else{
      cout << 'L';
      x--;
    }
    countx++;
  }
  while(y!=0){
    if(y<0){
      cout << 'U';
      y++;
    }
    else{
      cout << 'D';
      y--;
    }
    county++;
  }
  
  if(signx == 1){
    x += countx;
  }
  else{
    x -= countx;
  }
  
  if(signy == 1){
    y += county;
  }
  else{
    y -= county;
  }
  
  
  if(signy == 1){
    cout << 'D';
  }
  else{
    cout << 'U';
  }
  if(signx == 1){
    cout << 'R';
  }
  else{
    cout << 'L';
  }
  
  if(signy == 1){
    cout << 'D';
  }
  else{
    cout << 'U';
  }
  if(signx == 1){
    cout << 'R';
  }
  else{
    cout << 'L';
  }
  
  
   while(x!=0){
    if(x<0){
      cout << 'L';
      x++;
    }
    else{
      cout << 'R';
      x--;
    }
    countx++;
  }
  while(y!=0){
    if(y<0){
      cout << 'D';
      y++;
    }
    else{
      cout << 'U';
      y--;
    }
    county++;
  }
  
  if(signx == 1){
    cout << 'L';
  }
  else{
    cout << 'R';
  }
  if(signy == 1){
    cout << 'U';
  }
  else{
    cout << 'D';
  }
  
  
}

Compiler output:
a.cc: In function 'int main()':
a.cc:21:14: error: expected ';' before '}' token
   21 |     signy = 1
      |              ^
      |              ;
   22 |   }
      |   ~
Language: C++

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

int main(){
 int a,b,aa,bb; cin >> a >> b >> aa >> bb;
 int x = aa - a;
 int y = bb - b;
  
  int signx , signy = 0,0;
  if(x<0){
    signx = -1;
  }
  else{
    signx = 1;
  }
  
  if(y<0){
    signy = -1;
  }
  else{
    signy = 1
  }
  
  int countx,county = 0,0;
  while(x!=0){
    if(x<0){
      cout << 'R';
      x++;
    }
    else{
      cout << 'L';
      x--;
    }
    countx++;
  }
  while(y!=0){
    if(y<0){
      cout << 'U';
      y++;
    }
    else{
      cout << 'D';
      y--;
    }
    county++;
  }
  
  if(signx == 1){
    x += countx;
  }
  else{
    x -= countx;
  }
  
  if(signy == 1){
    y += county;
  }
  else{
    y -= county;
  }
  
  while(x!=0){
    if(x<0){
      cout << 'L';
      x++;
    }
    else{
      cout << 'R';
      x--;
    }
    countx++;
  }
  while(y!=0){
    if(y<0){
      cout << 'D';
      y++;
    }
    else{
      cout << 'U';
      y--;
    }
    county++;
  }
  
    
  if(signx == 1){
    x += countx;
  }
  else{
    x -= countx;
  }
  
  if(signy == 1){
    y += county;
  }
  else{
    y -= county;
  }
  
  if(signx == 1){
    cout << 'L';
  }
  else{
    cout << 'R';
  }
  if(signy == 1){
    cout << 'U';
  }
  else{
    cout << 'D';
  }
  
  while(x!=0){
    if(x<0){
      cout << 'R';
      x++;
    }
    else{
      cout << 'L';
      x--;
    }
    countx++;
  }
  while(y!=0){
    if(y<0){
      cout << 'U';
      y++;
    }
    else{
      cout << 'D';
      y--;
    }
    county++;
  }
  
  if(signx == 1){
    x += countx;
  }
  else{
    x -= countx;
  }
  
  if(signy == 1){
    y += county;
  }
  else{
    y -= county;
  }
  
  
  if(signy == 1){
    cout << 'D';
  }
  else{
    cout << 'U';
  }
  if(signx == 1){
    cout << 'R';
  }
  else{
    cout << 'L';
  }
  
  if(signy == 1){
    cout << 'D';
  }
  else{
    cout << 'U';
  }
  if(signx == 1){
    cout << 'R';
  }
  else{
    cout << 'L';
  }
  
  
   while(x!=0){
    if(x<0){
      cout << 'L';
      x++;
    }
    else{
      cout << 'R';
      x--;
    }
    countx++;
  }
  while(y!=0){
    if(y<0){
      cout << 'D';
      y++;
    }
    else{
      cout << 'U';
      y--;
    }
    county++;
  }
  
  if(signx == 1){
    cout << 'L';
  }
  else{
    cout << 'R';
  }
  if(signy == 1){
    cout << 'U';
  }
  else{
    cout << 'D';
  }
  
  
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:25: error: expected unqualified-id before numeric constant
    9 |   int signx , signy = 0,0;
      |                         ^
a.cc:21:14: error: expected ';' before '}' token
   21 |     signy = 1
      |              ^
      |              ;
   22 |   }
      |   ~           
a.cc:24:25: error: expected unqualified-id before numeric constant
   24 |   int countx,county = 0,0;
      |                         ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
int main() {
  int sx,sy,tx,ty;
  cin >> sx >> sy >> tx >> ty;
  int xx = tx - sx;
  int yy = ty - sy;
  string rz = "";
  string lz = "";
  for (int i = 0; i < xx; i++) {
  rz += "R";
  lz += "L";
}
string dz = "";
string uz = "";
for (int i = 0; i < yy; i++) {
  dz += "D";
  uz += "U";
}

string firs = uz + rz + dz + lz;
string secon = "D" + rz + "R" + uz + "ULUL" + lz + dz + "DR"

cout << firs + secon << endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:24:1: error: expected ',' or ';' before 'cout'
   24 | cout << firs + secon << endl;
      | ^~~~
Language: C++

#include <bits/stdc++.h>
using namespace std;
int main() {
  int sx,sy,tx,ty;
  cin >> sx >> sy >> tx >> ty;
  int xx = tx - sx;
  int yy = ty - sy;
  string one = "U" * yy + "R" * xx;
  string two = "D" * yy + "L" * xx;
  string three = "D" + "R" * (xx + 1) + "U" * (yy + 1) + "L";
  string four = "U" + "L" * (xx + 1) + "D" * (yy + 1) + "R";
  cout << one + two + three + four << endl; 
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:20: error: invalid operands of types 'const char [2]' and 'int' to binary 'operator*'
    8 |   string one = "U" * yy + "R" * xx;
      |                ~~~ ^ ~~
      |                |     |
      |                |     int
      |                const char [2]
a.cc:8:31: error: invalid operands of types 'const char [2]' and 'int' to binary 'operator*'
    8 |   string one = "U" * yy + "R" * xx;
      |                           ~~~ ^ ~~
      |                           |     |
      |                           |     int
      |                           const char [2]
a.cc:9:20: error: invalid operands of types 'const char [2]' and 'int' to binary 'operator*'
    9 |   string two = "D" * yy + "L" * xx;
      |                ~~~ ^ ~~
      |                |     |
      |                |     int
      |                const char [2]
a.cc:9:31: error: invalid operands of types 'const char [2]' and 'int' to binary 'operator*'
    9 |   string two = "D" * yy + "L" * xx;
      |                           ~~~ ^ ~~
      |                           |     |
      |                           |     int
      |                           const char [2]
a.cc:10:28: error: invalid operands of types 'const char [2]' and 'int' to binary 'operator*'
   10 |   string three = "D" + "R" * (xx + 1) + "U" * (yy + 1) + "L";
      |                        ~~~ ^ ~~~~~~~~
      |                        |         |
      |                        |         int
      |                        const char [2]
a.cc:10:45: error: invalid operands of types 'const char [2]' and 'int' to binary 'operator*'
   10 |   string three = "D" + "R" * (xx + 1) + "U" * (yy + 1) + "L";
      |                                         ~~~ ^ ~~~~~~~~
      |                                         |         |
      |                                         |         int
      |                                         const char [2]
a.cc:11:27: error: invalid operands of types 'const char [2]' and 'int' to binary 'operator*'
   11 |   string four = "U" + "L" * (xx + 1) + "D" * (yy + 1) + "R";
      |                       ~~~ ^ ~~~~~~~~
      |                       |         |
      |                       |         int
      |                       const char [2]
a.cc:11:44: error: invalid operands of types 'const char [2]' and 'int' to binary 'operator*'
   11 |   string four = "U" + "L" * (xx + 1) + "D" * (yy + 1) + "R";
      |                                        ~~~ ^ ~~~~~~~~
      |                                        |         |
      |                                        |         int
      |                                        const char [2]
Language: C++

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

string add_root(string root, string direct, int count) {
  for (int i < 0; i < count; i++) {
    root = root + direct;
  }
  return root;
}


int main() {
  int sx, sy, tx, ty;
  cin >> sx >> sy >> tx >> ty;
  int dx = tx - sx, dy = ty - sy;
  string r;
  r = add_root(r, "R", dx);
  r = add_root(r, "U", dy);
  r = add_root(r, "L", dx);
  r = add_root(r, "D", dy + 1);
  r = add_root(r, "R", dx + 1);
  r = add_root(r, "U", dy + 1);
  r = add_root(r, "L", 1);
  r = add_root(r, "U", 1);
  r = add_root(r, "L", dx + 1);
  r = add_root(r, "D", dy + 1);
  r = add_root(r, "R", 1);
  
  cout << r << endl;
}

Compiler output:
a.cc: In function 'std::string add_root(std::string, std::string, int)':
a.cc:5:13: error: expected ';' before '<' token
    5 |   for (int i < 0; i < count; i++) {
      |             ^~
      |             ;
a.cc:5:14: error: expected primary-expression before '<' token
    5 |   for (int i < 0; i < count; i++) {
      |              ^
a.cc:5:28: error: expected ')' before ';' token
    5 |   for (int i < 0; i < count; i++) {
      |       ~                    ^
      |                            )
a.cc:5:30: error: 'i' was not declared in this scope
    5 |   for (int i < 0; i < count; i++) {
      |                              ^
Language: C++

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

using namespace std;

int main() {
  int sx, sy, tx, ty;
  cin >> sx >> sy >> tx >> ty;
  
  int dx = tx - sx;
  int dy = ty - sy;
  
  string outstr = str(dy, 'U') + str(dx, 'R') + str(dy, 'D') + str(dx, 'L');
  outstr += 'L' + str(dy + 1, 'U') + str(dx + 1, 'R') + 'D';
  outstr += 'R' + str(dy + 1, 'D') + str(dx + 1, 'L') + 'U';
  
  cout << outstr << endl;
  
  return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:15:19: error: 'str' was not declared in this scope; did you mean 'std'?
   15 |   string outstr = str(dy, 'U') + str(dx, 'R') + str(dy, 'D') + str(dx, 'L');
      |                   ^~~
      |                   std
Language: C++

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

using namespace std;

int main() {
  int sx, sy, tx, ty;
  cin >> sx >> sy >> tx >> ty;
  
  int dx = tx - sx;
  int dy = ty - sy;
  
  string outstr = 'U' * dy + 'R' * dx + 'D' * dy + 'L' * dx;
  outstr += 'L' + 'U' * (dy + 1) + 'R' * (dx + 1) + 'D';
  outstr += 'R' + 'D' * (dy + 1) + 'L' * (dx + 1) + 'U';
  
  cout << outstr << endl;
  
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:15:50: error: conversion from 'int' to non-scalar type 'std::string' {aka 'std::__cxx11::basic_string<char>'} requested
   15 |   string outstr = 'U' * dy + 'R' * dx + 'D' * dy + 'L' * dx;
      |                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~
Language: C++

#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;

int main() {
  int sx,sy,tx,ty;
  cin >> sx >> sy >> tx >> ty;
  
  int dx = abs(tx-sx);
  int dy = abs(ty-sy);
  
  char rightup[] = ['U','R','D','L','D','R','U','L','U','L','D','R'];
  char leftdown[] = ['D','L','U','R','R','D','L','U','L','U','R','D'];
  
  for(int i = 0; i < dx; i++) printf("U");
  for(int i = 0; i < dy; i++) printf("R");
  for(int i = 0; i < dx; i++) printf("D");
  for(int i = 0; i < dy; i++) printf("L");

  printf("D");
  for(int i = 0; i < dx+1; i++) printf("R");
  for(int i = 0; i < dy+1; i++) printf("U");
  printf("L");
  printf("U");
  for(int i = 0; i < dx+1; i++) printf("L");
  for(int i = 0; i < dy+1; i++) printf("D");
  printf("R");
  
  
 return 0; 
}

Compiler output:
a.cc: In function 'int main()':
a.cc:13:21: error: expected identifier before 'U'
   13 |   char rightup[] = ['U','R','D','L','D','R','U','L','U','L','D','R'];
      |                     ^~~
a.cc:13:24: error: expected ']' before ',' token
   13 |   char rightup[] = ['U','R','D','L','D','R','U','L','U','L','D','R'];
      |                        ^
      |                        ]
a.cc: In lambda function:
a.cc:13:24: error: expected '{' before ',' token
a.cc: In function 'int main()':
a.cc:13:20: error: initializer fails to determine size of 'rightup'
   13 |   char rightup[] = ['U','R','D','L','D','R','U','L','U','L','D','R'];
      |                    ^~~~
a.cc:13:20: error: array must be initialized with a brace-enclosed initializer
a.cc:13:25: error: expected unqualified-id before 'R'
   13 |   char rightup[] = ['U','R','D','L','D','R','U','L','U','L','D','R'];
      |                         ^~~
a.cc:14:22: error: expected identifier before 'D'
   14 |   char leftdown[] = ['D','L','U','R','R','D','L','U','L','U','R','D'];
      |                      ^~~
a.cc:14:25: error: expected ']' before ',' token
   14 |   char leftdown[] = ['D','L','U','R','R','D','L','U','L','U','R','D'];
      |                         ^
      |                         ]
a.cc: In lambda function:
a.cc:14:25: error: expected '{' before ',' token
a.cc: In function 'int main()':
a.cc:14:21: error: initializer fails to determine size of 'leftdown'
   14 |   char leftdown[] = ['D','L','U','R','R','D','L','U','L','U','R','D'];
      |                     ^~~~
a.cc:14:21: error: array must be initialized with a brace-enclosed initializer
a.cc:14:26: error: expected unqualified-id before 'L'
   14 |   char leftdown[] = ['D','L','U','R','R','D','L','U','L','U','R','D'];
      |                          ^~~
Language: C++

#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;

int main() {
  int sx,sy,tx,ty;
  cin >> sx >> sy >> tx >> ty;
  
  int dx = abs(tx-sx);
  int dy = abs(ty-sy);
  
  char[] rightup = ['U','R','D','L','D','R','U','L','U','L','D','R'];
  char[] leftdown = ['D','L','U','R','R','D','L','U','L','U','R','D'];
  
  for(int i = 0; i < dx; i++) printf("U");
  for(int i = 0; i < dy; i++) printf("R");
  for(int i = 0; i < dx; i++) printf("D");
  for(int i = 0; i < dy; i++) printf("L");

  printf("D");
  for(int i = 0; i < dx+1; i++) printf("R");
  for(int i = 0; i < dy+1; i++) printf("U");
  printf("L");
  printf("U");
  for(int i = 0; i < dx+1; i++) printf("L");
  for(int i = 0; i < dy+1; i++) printf("D");
  printf("R");
  
  
 return 0; 
}

Compiler output:
a.cc: In function 'int main()':
a.cc:13:7: error: structured binding declaration cannot have type 'char'
   13 |   char[] rightup = ['U','R','D','L','D','R','U','L','U','L','D','R'];
      |       ^~
a.cc:13:7: note: type must be cv-qualified 'auto' or reference to cv-qualified 'auto'
a.cc:13:7: error: empty structured binding declaration
a.cc:13:10: error: expected initializer before 'rightup'
   13 |   char[] rightup = ['U','R','D','L','D','R','U','L','U','L','D','R'];
      |          ^~~~~~~
a.cc:14:7: error: structured binding declaration cannot have type 'char'
   14 |   char[] leftdown = ['D','L','U','R','R','D','L','U','L','U','R','D'];
      |       ^~
a.cc:14:7: note: type must be cv-qualified 'auto' or reference to cv-qualified 'auto'
a.cc:14:7: error: empty structured binding declaration
a.cc:14:10: error: expected initializer before 'leftdown'
   14 |   char[] leftdown = ['D','L','U','R','R','D','L','U','L','U','R','D'];
      |          ^~~~~~~~
Language: C++

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

int main() {
  int sx, sy, tx, ty;
  cin >> sx >> sy >> tx >> ty;
  
  int dx = tx - sx;
  int dy = ty - sy;
  
  rep(i, dx) {
    cout << "R";
  }

  rep(i, dy) {
    cout << "U";
  }

  rep(i, dx) {
    cout << "L";
  }

  rep(i, dy) {
    cout << "D";
  }
  
}


Compiler output:
a.cc: In function 'int main()':
a.cc:11:7: error: 'i' was not declared in this scope
   11 |   rep(i, dx) {
      |       ^
a.cc:11:3: error: 'rep' was not declared in this scope
   11 |   rep(i, dx) {
      |   ^~~
Language: C++

#include<bits/stdc++.h>
#include <iostream>
#include <string>
#include <cmath>
using namespace std;
#define ll long long
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define FOR(i,a,b) for(ll i=(a);i<(b);i++)
#define FORR(i,a,b)for(ll i=(a);i<=(b);i++)
#define repR(i,n) for(ll i=n;i>=0;i--)
#define all(v)(v).begin(),(v).end()
#define rall(v)(v).rbegin(),(v).rend()
#define F first
#define S second
#define pb push_back
#define pu push
#define COUT(x) cout<<(x)<<endl
#define PQ priority_queue<ll>
#define PQR priority_queue<ll,vector<ll>,greater<ll>>
#define YES(n) cout << ((n) ? "YES" : "NO"  ) << endl
#define Yes(n) cout << ((n) ? "Yes" : "No"  ) << endl
#define mp make_pair
#define maxs(x,y) (x = max(x,y))
#define mins(x,y) (x = min(x,y))
#define sz(x) (int)(x).size()
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const ll MOD = 1000000007LL;
const ll INF = 1LL << 60;
using vll = vector<ll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvll = vector<vll>;
using vstr = vector<string>;
using pll = pair<ll, ll>;
int main(){
  ll sx,sy,tx,ty;
  cin>>sx>>sy>>tx>>ty;
  vector<char> ans(0);
  rep(i,tx-sx){
    ans.pb('R');
  }
  rep(i,ty-sy){
    ans.pb('U');
  }
  rep(i,tx-sx){
    ans.pb('L');
  }
  rep(i,ty-sy){
    ans.pb('D');
  }
  ans.pb('D');
  rep(i,ts-sx+1){
    ans.pb('R');
  }
  rep(i,ty-sy+1){
    ans.pb('U');
  }
  ans.pb('L');
  ans.pb('U');
  rep(i,ts-sx+1){
    ans.pb('L');
  }
  rep(i,ty-sy+1){
    ans.pb('D');
  }
  ans.pb('R');
  rep(i,sz(ans)){
    cout<<ans[i];
  }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:53:9: error: 'ts' was not declared in this scope; did you mean 'ty'?
   53 |   rep(i,ts-sx+1){
      |         ^~
a.cc:7:39: note: in definition of macro 'rep'
    7 | #define rep(i, n) for (ll i = 0; i < (n); i++)
      |                                       ^
a.cc:61:9: error: 'ts' was not declared in this scope; did you mean 'ty'?
   61 |   rep(i,ts-sx+1){
      |         ^~
a.cc:7:39: note: in definition of macro 'rep'
    7 | #define rep(i, n) for (ll i = 0; i < (n); i++)
      |                                       ^
Language: C++

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

bool check(int nx, int ny, vector<pair<int, int> >vis)
{
	for(int i = 0; i < vis.size(); i++)
    {
    	if(nx == v[i].first && ny == v[i].second)
          	return true;
    }
  	return false;
}

void fun(queue<pair<int, int> > &q, int sx, int sy, int tx, int ty, vector<pair<int, int> >&vis, int row[], int col[])
{
  	vis[sx][sy] = true;
	while(!q.empty())
    {
    	pair<int, int> t = q.front();
      	q.pop();
      	if(t.first == tx && t.second == ty)
          break;
      	/*if((t.first == sx && t.second == sy) || (t.first == tx && t.second == ty))
      		vis[t.first][t.second] = true;*/
      	for(int i = 0; i < 4; i++)
        {
        	int nx = t.first + row[i];
          	int ny = t.second + col[i];
          	if(nx >= -1000 && nx <= 1000 && ny >= -1000 && ny <= 1000 && check(nx, ny, vis) == false)
            {
              	//vis[nx][ny] = true;
              	vis.push_back(make_pair(nx, ny));
            	q.push(make_pair(nx, ny));
              	if(row[i] == 1)
                  cout<<"D";
              	else if(row[i] == -1)
                  cout<<"U";
              	else if(col[i] == 1)
                  cout<<"R";
              	else
                  cout<<"L";
            }
        }
    }
}

int main()
{
  	int sx, sy, tx, ty;
  	cin>>sx>>sy>>tx>>ty;
  	/*vector<vector<bool> > vis( 1000 , vector<int> (1000, false));*/
  	vector<pair<int, int> >vis;
  	int row[] = {-1, 0, 0, 1};
  	int col[] = {0, 1, -1, 0};
  	queue<pair<int, int> >q;
  	q.push(make_pair(sx, sy));
  	fun(q, sx, sy, tx, ty, vis, row, col);
  	fun(q, tx, ty, sx, sy, vis, row, col);
	fun(q, sx, sy, tx, ty, vis, row, col);
  	fun(q, tx, ty, sx, sy, vis, row, col);
	return 0;
}

Compiler output:
a.cc: In function 'bool check(int, int, std::vector<std::pair<int, int> >)':
a.cc:8:18: error: 'v' was not declared in this scope
    8 |         if(nx == v[i].first && ny == v[i].second)
      |                  ^
a.cc: In function 'void fun(std::queue<std::pair<int, int> >&, int, int, int, int, std::vector<std::pair<int, int> >&, int*, int*)':
a.cc:16:16: error: no match for 'operator[]' (operand types are '__gnu_cxx::__alloc_traits<std::allocator<std::pair<int, int> >, std::pair<int, int> >::value_type' {aka 'std::pair<int, int>'} and 'int')
   16 |         vis[sx][sy] = true;
      |                ^
Language: C++

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

bool check(int nx, int ny, vector<pair<int, int> >vis)
{
	for(int i = 0; i < vis.size(); i++)
    {
    	if(nx == v[i].first && ny == v[i].second)
          	return true;
    }
  	return false;
}

void fun(queue<pair<int, int> > &q, int sx, int sy, int tx, int ty, vector<pair<int, int> >&vis, int row[], int col[])
{
  	vis[sx][sy] = true;
	while(!q.empty())
    {
    	pair<int, int> t = q.front();
      	q.pop();
      	if(t.first == tx && t.second == ty)
          break;
      	/*if((t.first == sx && t.second == sy) || (t.first == tx && t.second == ty))
      		vis[t.first][t.second] = true;*/
      	for(int i = 0; i < 4; i++)
        {
        	int nx = t.first + row[i];
          	int ny = t.second + col[i];
          	if(nx >= -1000 && nx <= 1000 && ny >= -1000 && ny <= 1000 && check(nx, ny, vis) == false)
            {
              	//vis[nx][ny] = true;
              	vis.push(make_pair(nx, ny));
            	q.push(make_pair(nx, ny));
              	if(row[i] == 1)
                  cout<<"D";
              	else if(row[i] == -1)
                  cout<<"U";
              	else if(col[i] == 1)
                  cout<<"R";
              	else
                  cout<<"L";
            }
        }
    }
}

int main()
{
  	int sx, sy, tx, ty;
  	cin>>sx>>sy>>tx>>ty;
  	/*vector<vector<bool> > vis( 1000 , vector<int> (1000, false));*/
  	vector<pair<int, int> >vis;
  	int row[] = {-1, 0, 0, 1};
  	int col[] = {0, 1, -1, 0};
  	queue<pair<int, int> >q;
  	q.push(make_pair(sx, sy));
  	fun(q, sx, sy, tx, ty, vis, row, col);
  	fun(q, tx, ty, sx, sy, vis, row, col);
	fun(q, sx, sy, tx, ty, vis, row, col);
  	fun(q, tx, ty, sx, sy, vis, row, col);
	return 0;
}

Compiler output:
a.cc: In function 'bool check(int, int, std::vector<std::pair<int, int> >)':
a.cc:8:18: error: 'v' was not declared in this scope
    8 |         if(nx == v[i].first && ny == v[i].second)
      |                  ^
a.cc: In function 'void fun(std::queue<std::pair<int, int> >&, int, int, int, int, std::vector<std::pair<int, int> >&, int*, int*)':
a.cc:16:16: error: no match for 'operator[]' (operand types are '__gnu_cxx::__alloc_traits<std::allocator<std::pair<int, int> >, std::pair<int, int> >::value_type' {aka 'std::pair<int, int>'} and 'int')
   16 |         vis[sx][sy] = true;
      |                ^
a.cc:32:21: error: 'class std::vector<std::pair<int, int> >' has no member named 'push'
   32 |                 vis.push(make_pair(nx, ny));
      |                     ^~~~
Language: C++

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

int main(){
  int sx,sy,tx,ty;
  cin>>sx>>sy>>tx>>ty;
  rep(i,ty-tx){
    cout<<'U';
  }
  rep(i,tx-sx){
    cout<<'R';
  }
  rep(i,ty-tx){
    cout<<'D';
  }
  rep(i,tx-sx){
    cout<<'L';
  }
  cout<<'L';
  rep(i,ty-tx+1){
    cout<<'U';
  }
  rep(i,tx-sx){
    cout<<'R';
  }
  cout<<"DR"
  rep(i,ty-tx){
    cout<<'D';
  }
  rep(i,tx-sx){
    cout<<'L';
  }
  cout<<'U';
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:29:13: error: expected ';' before 'for'
   29 |   cout<<"DR"
      |             ^
      |             ;
a.cc:30:7: error: 'i' was not declared in this scope
   30 |   rep(i,ty-tx){
      |       ^
a.cc:2:30: note: in definition of macro 'rep'
    2 | #define rep(i,n) for(int i=0;i<(n);i++)
      |                              ^
Language: C++

//おまじないc++
//おまじないc++
#include <iostream>
#include<cmath>
#include<vector>
#include <algorithm>
using namespace std;
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(),(x).end()
 
int main() {
 
int main() {
  int sx,sy,tx,ty;
  cin>>sx>>sy>>tx>>ty;
  
  int dx=tx-sx;
  int dy=ty-sy;
  
  for(int i=0;i<dx;i++){
    cout<<'R';
  }
  
  
  for(int i=0;i<dy;i++){
    cout<<'U';
  }
  
  for(int i=0;i<dx;i++){
    cout<<'L';
  }
  rep(i,dy){
    cout<<'D';
  }
  
  
  cout<<'D';
  
  for(int i=0;i<dx;i++){
    cout<<'R';
  }
  
  cout<<'R'<<'U';
  
   for(int i=0;i<dy;i++){
    cout<<'U';
  }
  
  
  cout<<'L'<<'U';
  
  for(int i=0;i<dx;i++){
    cout<<'L';
  }
  cout<<'L'<<'D';
  
  rep(i,dy){
    cout<<'D';
  }
  
  cout<<'R';
  
}
  
  
  
  
  
  
  

Compiler output:
a.cc: In function 'int main()':
a.cc:13:9: warning: empty parentheses were disambiguated as a function declaration [-Wvexing-parse]
   13 | int main() {
      |         ^~
a.cc:13:9: note: remove parentheses to default-initialize a variable
   13 | int main() {
      |         ^~
      |         --
a.cc:13:9: note: or replace parentheses with braces to value-initialize a variable
a.cc:13:12: error: a function-definition is not allowed here before '{' token
   13 | int main() {
      |            ^
a.cc:63:2: error: expected '}' at end of input
   63 | }
      |  ^
a.cc:11:12: note: to match this '{'
   11 | int main() {
      |            ^
Language: C++

import java.util.*;
 
public class Main{
  public static void main(String[]args){
    Scanner sc =  new Scanner(System.in);
    String[] S = sc.nextLine().split(" ");
    int sx = Integer.parseInt(S[0]);
    int sy = Integer.parseInt(S[1]);
    int tx = Integer.parseInt(S[2]);
    int ty = Integer.parseInt(S[3]);
    
    int a = tx-sx;
    int b = ty-sy;
    
    String ans = "", ans1 = "", ans2 = "", ans3 = "", ans4 = "";
    for(int i = 0; i < a; i++){
      ans1 += "R";
      ans3 += "L";
    }
    for(int i = 0; i < b; i++){
      ans2 += "U";
      ans4 += "D";
    }
    ans += ans1 + ans2 + ans3 + ans4;
    ans1 = "";
    ans2 = "";
    ans3 = "";
    ans4 = "";
    for(int i = 0; i < a+1; i++){
      ans1 += "R";
      ans3 += "L";
    }
    for(int i = 0; i < b+1; i++){
      ans2 += "U";
      ans4 += "D";
    }
    ans += "D" + ans1 + ans2 + "L" + "U" + ans3 + ans4 + "R";
    System.out.println(ans);
  }
}

Compiler output:
a.cc:1:1: error: 'import' does not name a type
    1 | import java.util.*;
      | ^~~~~~
a.cc:1:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:3:1: error: expected unqualified-id before 'public'
    3 | public class Main{
      | ^~~~~~
Language: C++

#include <unordered_set>
#include <iostream>
#include <algorithm>
#include <vector>

bool is_in_indices(int a, int b, std::unordered_set<std::string>* indices) {
  char key[6];
  sprintf(key, "%d_%d", a, b);
  return indices->count(std::string(key)) > 0;
}

void walk(int cx, int tx, int cy, int ty, std::unordered_set<std::string>* indices, std::vector<std::string>* result) {
  if (cx == tx && cy == ty) {
    return;
  }
  if (cx < tx) {
    if (is_in_indices(cx + 1, cy, indices)) {
      result->push_back("R");
      return walk(cx + 1, tx, cy, ty, indices, result);
    }
  }
  if (cy < ty) {
    if (is_in_indices(cx, cy + 1, indices)) {
      result->push_back("D");
      return walk(cx, tx, cy + 1, ty, indices, result);
    }
  }
  if (cx > tx) {
    if (is_in_indices(cx - 1, cy, indices)) {
      result->push_back("L");
      return walk(cx - 1, tx, cy, ty, indices, result);
    }
  }
  if (cy > ty) {
    if (is_in_indices(cx, cy - 1, indices)) {
      result->push_back("U");
      return walk(cx, tx, cy - 1, ty, indices, result);
    }
  }

  if (is_in_indices(cx + 1, cy, indices)) {
    result->push_back("R");
    return walk(cx, tx, cy - 1, ty, indices, result);
  }
  if (is_in_indices(cx - 1, cy, indices)) {
    result->push_back("L");
    return walk(cx, tx, cy - 1, ty, indices, result);
  }
  if (is_in_indices(cx, cy + 1, indices)) {
    result->push_back("D");
    return walk(cx, tx, cy - 1, ty, indices, result);
  }
  if (is_in_indices(cx, cy - 1, indices)) {
    result->push_back("U");
    return walk(cx, tx, cy - 1, ty, indices, result);
  }
}

int main() {
  int sx = 0;
  int sy = 0;
  int tx = 0;
  int ty = 0;
  std::cin >> sx;
  std::cin >> sy;
  std::cin >> tx;
  std::cin >> ty;
  
  std::unordered_set<std::string> indices;
  std::vector<std::string> result;
  
  walk(sx, sy, tx, ty, &indices, &result);
  walk(tx, ty, sx, sy, &indices, &result);
  walk(sx, sy, tx, ty, &indices, &result);
  walk(tx, ty, sx, sy, &indices, &result);
  
  for (auto p&: result) {
    printf("%s", p.c_str());
  }
  printf("\n");
}

Compiler output:
a.cc: In function 'int main()':
a.cc:77:14: error: expected ';' before '&' token
   77 |   for (auto p&: result) {
      |              ^
      |              ;
a.cc:77:15: error: expected primary-expression before ':' token
   77 |   for (auto p&: result) {
      |               ^
a.cc:77:15: error: expected ';' before ':' token
   77 |   for (auto p&: result) {
      |               ^
      |               ;
a.cc:77:15: error: expected primary-expression before ':' token
a.cc:77:15: error: expected ')' before ':' token
   77 |   for (auto p&: result) {
      |       ~       ^
      |               )
a.cc:77:15: error: expected primary-expression before ':' token
Language: C++

#include <iostream>
# include <string>
int main(void) {
  int sx, sy, tx, ty;
  cin >> sx >> endl;
  cin >> sy >> endl;
  cin >> tx >> endl;
  cin >> ty >> endl;
  string box1, box2;
  int x_diff = tx- sx;
  int y_diff = ty - sy;   
    box1 = string(y_diff, "U");
    box1 += string(x_diff+1, "R");
    box1 += string(y_diff+1, "D");
    box1 += string(x_diff+1, "L");
    box1 += string(1, "U");
    
    box2 = string(x_diff, "R");
    box2 += string(y_diff+1, "U");
    box2 += string(x_diff+1, "L");
    box2 += string(y_diff+1, "D");
    box2 += string(1, "R");
    
    cout << box1 << box2 << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    5 |   cin >> sx >> endl;
      |   ^~~
      |   std::cin
In file included from a.cc:1:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:5:16: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    5 |   cin >> sx >> endl;
      |                ^~~~
      |                std::endl
In file included from /usr/include/c++/14/iostream:41:
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:9:3: error: 'string' was not declared in this scope
    9 |   string box1, box2;
      |   ^~~~~~
a.cc:9:3: note: suggested alternatives:
In file included from /usr/include/c++/14/iosfwd:41,
                 from /usr/include/c++/14/ios:40,
                 from /usr/include/c++/14/ostream:40:
/usr/include/c++/14/bits/stringfwd.h:77:33: note:   'std::string'
   77 |   typedef basic_string<char>    string;
      |                                 ^~~~~~
In file included from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44:
/usr/include/c++/14/string:76:11: note:   'std::pmr::string'
   76 |     using string    = basic_string<char>;
      |           ^~~~~~
a.cc:12:5: error: 'box1' was not declared in this scope
   12 |     box1 = string(y_diff, "U");
      |     ^~~~
a.cc:18:5: error: 'box2' was not declared in this scope
   18 |     box2 = string(x_diff, "R");
      |     ^~~~
a.cc:24:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   24 |     cout << box1 << box2 << endl;
      |     ^~~~
      |     std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~