Xor sum

#include <iostream>
#include <vector>
using namespace std;

int main() {
    int n, q;
    cin >> n >> q;

    vector<int> arr(n);
    for (int i = 0; i < n; ++i) {
        cin >> arr[i];
    }

    vector<int> prefix(n+1, 0);
    for (int i = 1; i <= n; ++i) {
        prefix[i] = prefix[i-1] ^ arr[i-1];
    }

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

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED