Xor sum

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

#define I_2D(row, col, width) ((row) * (width) + (col))
#define PRINT_ARR(arr, n)                                                      \
  do {                                                                         \
    for (int i = 0; i < n; i++) {                                              \
      cout << arr[i] << " ";                                                   \
    }                                                                          \
    cout << "\n";                                                              \
  } while (0)

typedef long long ll;

#define DEF_VAL 0

int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);

  int n, q;
  cin >> n >> q;

  ll arr[n];
  memset(arr, 0, n*sizeof(ll));

  for (int i = 0; i < n; i++) {
    cin >> arr[i];
    if (i != 0) {
      arr[i] ^= arr[i-1];
    }
  }

  int a, b;
  ll s;
  for (int i = 0; i < q; i++) {
    cin >> a >> b;
    a--, b--;
    s = arr[b];
    if (a > 0) {
      s ^= arr[a-1];
    }
    cout << s << endl;
  }
  return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED