Shared code

#include<bits/stdc++.h>
using namespace std;
 
typedef long long int ll;
#define IOS ios_base::sync_with_stdio(0);  cin.tie(0); cout.tie(0);
 
 
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
 
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>order_set;
typedef pair<int, int>pr;
#define all(i)     i.begin() , i.end()
#define ft     first
#define sn     second
#define pb push_back
 
#define en "\n"
#define dbg cout<<"rony\n"
 
#define MAXN 200010
#define inf 1e6+5
const ll mod = 1e9 + 7;
 
int n;
int a[MAXN];
 
struct segment_tree
{
    struct NODE {
        int st , EN, value;// start , end
 
        void init(int L, int R) {
            st = L, EN = R;
            if (L == R) value = a[L];
        }
    } g[3 * MAXN];
 
    void fill_CN(NODE &CN, NODE &LN, NODE &RN) // fill_current_node
    {
        CN.value = LN.value ^ RN.value;
    }
 
    void build(int CN, int L, int R)
    {
        g[CN].init(L, R);
 
        if (L == R ) return;
        int mid = (L + R) >> 1;
        int LN = CN << 1;
 
        build(LN, L, mid);
        build(LN | 1, mid + 1, R);
 
        fill_CN (g[CN], g[LN] , g[LN | 1]);
    }
 
    int query(int CN, int L, int R)
    {
        int x = g[CN].st;
        int y = g[CN].EN;
        if (y < L || x > R) return 0;
 
        if (L <= x && R >= y ) return g[CN].value;
 
        int LN = CN << 1;
 
        int ans = query(LN, L, R);
        ans ^= query(LN | 1, L, R);
        return ans;
    }
 
} s_tree;
void solve()
{
    int q;
    cin >> n >> q;
    for (int i = 1; i <= n; i++) cin >> a[i];
 
    s_tree.build(1, 1, n);
 
    while (q--)
    {
        int x, y;
        cin >> x >> y;
        cout << s_tree.query(1, x, y) << en;
    }
}
int main()
{
    IOS;
    ll t;
    t = 1;
 
    // cin >> t;
 
    int c = 0;
    while ( t-- )
    {
        // cout<<"Case "<<++c<<": ";
        solve();
    }
    return 0;
}