Xor sum

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
 
#define SEG_OP(a,b) a ^ b
 
const int N = 1<<19;
 
struct Seg {
  int S[N*2];
 
  Seg(int x = 0) {
    for (int i = N; i < N*2; ++i) S[i] = x;
    for (int i = N-1; i >= 1; --i) S[i] = SEG_OP(S[i*2], S[i*2+1]);
  }
  void set(int i, int x) {
    i |= N;
    S[i] = x;
    for (i /= 2; i >= 1; i /= 2) {
      S[i] = SEG_OP(S[i*2], S[i*2+1]);
    }
  }
  ll get(int a, int b, ll s = 0) {
    a |= N; b |= N;
    while (a <= b) {
      if (a % 2 == 1) s = SEG_OP(s, ll(S[a++]));
      if (b % 2 == 0) s = SEG_OP(s, ll(S[b--]));
      a /= 2; b /= 2;
    }
    return s;
  }
};
 
int n, q;
Seg S;
 
int main() {
	cin >> n >> q;
	for (int i = 0; i < n; ++i) {
		int x;
		cin >> x;
		S.set(i+1,x);
	}
	for (int i = 0; i < q; ++i) {
		int a, b;
		cin >> a >> b;
		cout << S.get(a,b) << '\n';
	}
	
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED