Submission #425017

#	Time	Username	Problem	Language	Result	Execution time	Memory
425017		MilosMilutinovic	XORanges (eJOI19_xoranges)	C++14	100 / 100	209 ms	11224 KiB

xoranges

#include <bits/stdc++.h>

using namespace std;

const int N = 3e5 + 5;
const int M = 4 * N;

int a[N], st[M][2];

void build(int node, int l, int r) {
  if (l > r) return;
  if (l == r) {
    st[node][l % 2] = a[l];
    return;
  }
  int mid = l + r >> 1;
  build(node * 2, l, mid);
  build(node * 2 + 1, mid + 1, r);
  st[node][0] = st[node * 2][0] ^ st[node * 2 + 1][0];
  st[node][1] = st[node * 2][1] ^ st[node * 2 + 1][1];
}

void update(int node, int l, int r, int pos) {
  if (l > r) {
    return;
  }
  if (l == r) {
    st[node][l % 2] = a[l];
    return;
  }
  int mid = l + r >> 1;
  if (pos <= mid) update(node * 2, l, mid, pos);
   else update(node * 2 + 1, mid + 1, r, pos);
  st[node][0] = st[node * 2][0] ^ st[node * 2 + 1][0];
  st[node][1] = st[node * 2][1] ^ st[node * 2 + 1][1];
}

int get(int node, int l, int r, int ll, int rr, int p) {
  if (l > r || l > rr || r < ll) return 0;
  if (ll <= l && r <= rr) return st[node][p];
  int mid = l + r >> 1;
  return get(node * 2, l, mid, ll, rr, p) ^ get(node * 2 + 1, mid + 1, r, ll, rr, p);
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, q;
  cin >> n >> q;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  build(1, 0, n - 1);
  while (q--) {
    int foo;
    cin >> foo;
    if (foo == 1) {
      int pos, x;
      cin >> pos >> x;
      --pos;
      a[pos] = x;
      update(1, 0, n - 1, pos);
    } else {
      int l, r;
      cin >> l >> r;
      --l, --r;
      if (l % 2 != r % 2) {
        cout << 0 << '\n';
        continue;
      }
      cout << get(1, 0, n - 1, l, r, l % 2) << '\n';
    }
  }
  return 0;
}

Compilation message (stderr)

xoranges.cpp: In function 'void build(int, int, int)':
xoranges.cpp:16:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   16 |   int mid = l + r >> 1;
      |             ~~^~~
xoranges.cpp: In function 'void update(int, int, int, int)':
xoranges.cpp:31:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   31 |   int mid = l + r >> 1;
      |             ~~^~~
xoranges.cpp: In function 'int get(int, int, int, int, int, int)':
xoranges.cpp:41:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   41 |   int mid = l + r >> 1;
      |             ~~^~~

• Subtask 1: 12 / 12
• Subtask 2: 18 / 18
• Subtask 3: 25 / 25
• Subtask 4: 20 / 20
• Subtask 5: 25 / 25