Lowest common Ancestor RMQ segment tree

#include "bits/stdc++.h"
using namespace std;
typedef long long int ll;
const int N = 1 << 10;
#define pb(x)  push_back(x);
#define L    cout << '\n'
vector < int > tree(N), v[N], euler(1),vis(N), ht(N), indx(N);
void Euler_tour(int node, int height){
    vis[node] = true;
    ht[node] = height ;
    euler.pb(node);

    for(auto i : v[node]){
        if(!vis[i]){
            Euler_tour(i, height + 1);
            euler.pb(node);
        }
    }
}
void build(int l, int r, int node){
    if(l == r){
        tree[node] = euler[l];
        return;
    }
    int mid = l + r >> 1;

    build(l, mid, 2 * node);
    build(mid + 1, r, 2 * node + 1);
    if(ht[tree[2 * node]] < ht[tree[2 * node + 1]])
        tree[node] = tree[2 * node];//,cout << euler[2*node] << ' ';
    else
        tree[node] = tree[2 * node + 1];//,cout << euler[2*node + 1] << ' ';
}
int query(int l, int r, int ql, int qr, int node){
    if(r < ql || l > qr)return -1;

    if(ql <= l && r <= qr)return tree[node];

    int mid = (l + r) >> 1;
    int x = query(l, mid, ql, qr, 2 * node);
    int y = query(mid + 1, r, ql , qr, 2 * node + 1);
    if(x == -1)return y;
    if(y == -1)return x;
    //cout << l << ' ' << r << ' ' << x << ' ' << y;L;
    if(ht[x] < ht[y])return x;
    else return y;
}
int main(){
 ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
       int n, l, r, i, x, y, q;
        cin >> n;
        cout << n << ' ';L;
       for(i = 0; i < n-1; i++){
           cin >> l >> r;
           v[l].pb(r);
           v[r].pb(l);
       }

       Euler_tour(1, 0);
       for(i = 1; i < euler.size(); i++){
           if(!indx[euler[i]]){
               indx[euler[i]] = i;
           }
       }

       //for(i =1; i < euler.size(); i++)cout << euler[i] << ' ';
       //L;
       //for(i = 1; i <= n; i++)
       //    cout << ht[i] << ' ';
       // It's time build segment tree
       //L;
       //for(i = 1; i <= n; i++)cout << indx[i] << ' ';
       //L;

        build(1, (int)euler.size() - 1, 1);
        cin >> q;
           while(q--){
               cin >> x >> y;
               //cout << x << ' ' << y;L;
               l = indx[x], r = indx[y];
               if(l > r)swap(l,r);
               //cout << l << ' ' << r;L;
       cout << query(1, (int)euler.size()-1 , l, r, 1);L;
    }





    return 0;
}