Xor sum

#include <iostream>
#include <vector>

using namespace std;

int main() {
    int n, q;
    cin >> n >> q;
    //prefix XOR array
    vector<int> pref(n + 1, 0);
    for (int i = 1; i <= n; i++) {
        int x;
        cin >> x;
        pref[i] = pref[i - 1] ^ x;  //xor sum
    }

    for (int i = 0; i < q; i++) {
        int a, b;
        cin >> a >> b;
        int ans = pref[b] ^ pref[a - 1];
        cout << ans << "\n";
    }
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED