Submission #1068861

#	Time	Username	Problem	Language	Result	Execution time	Memory
1068861		adrielcp	XORanges (eJOI19_xoranges)	C++17	0 / 100	1065 ms	2560 KiB

xoranges

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define debug(x) cout << #x << " " << (x) << endl;
#define all(x) x.begin(), x.end()
void pp(pair<int, int>&a) { cout << "{" << a.first << ", " << a.second << endl; }
void g(vector<int>&a) { cout << "{"; for (auto el : a) cout << el << ", "; cout << "}" << endl; }
void g(vector<pair<int, int>>&a) { cout << "{"; for (auto el : a) pp(el); cout << "}" << endl; }
#define DBG

struct Seg {
  vector<int> seg, a;
  Seg(vector<int> &b) {
    a = b;
    seg = vector<int>(a.size()*4);
  }

  void build(int idx, int l, int r) {
    if (l == r) seg[idx] = a[l];
    else {
      int mid = (l+r)>>1;
      build(idx*2, l, mid);
      build(idx*2+1, mid+1, r);
      seg[idx] = seg[idx*2] ^ seg[idx*2+1];
    }
  }

  int query(int idx, int l, int r, int ql, int qr) {
    if (l > qr || r < ql || l > r) return 0;
    if (l >= ql && r <= qr) return seg[idx];
    int mid = (l+r)>>1;
    return query(idx*2, l, mid, ql, qr) ^ query(idx*2+1, mid+1, r, ql, qr);
  }

  void update(int idx, int l, int r, int i, int v) {
    if (l == r) seg[idx] = v;
    else {
      int mid = (l+r)>>1;
      if (i <= mid) update(idx*2, l, mid, i, v);
      else update(idx*2+1, mid+1, r, i, v);
      seg[idx] = seg[idx*2] ^ seg[idx*2+1];
    }
  } 
};

void solve() {
  int n,q;cin>>n>>q;
  vector<int> a(n);
  for (int i = 0; i < n; i++) cin >> a[i];

  // even
  // 2 4 6 8 
  // 1 2 3 4
  // x/2

  // 1 3 5 7 9 10 (odd)
  // 1 2 3 4 5 6
  // x/2 + 1
  vector<int> odd{0}, even{0};
  for (int i = 0; i < n; i++) {
    if (i % 2 == 0) odd.push_back(a[i]);
    else even.push_back(a[i]);
  }
  Seg seg_odd(odd), seg_even(even);
  seg_odd.build(1, 1, odd.size());
  seg_even.build(1, 1, even.size());

  while (q--) {
    int t,x,y;cin>>t>>x>>y;
    if (t==1) {
      // upd
      // update(1, 1, n, x, y);
      if (x % 2 == 0) seg_even.update(1, 1, even.size(), x/2, y);
      else seg_odd.update(1, 1, odd.size(), x/2+1, y);
    } else {
      if ((y-x+1) % 2 == 0) cout << 0 << endl;
      else {
        if (x % 2 == 0) cout << seg_even.query(1, 1, even.size(), x/2, y/2) << endl;
        else cout << seg_odd.query(1, 1, odd.size(), x/2+1, y/2+1) << endl;
      }
    }
  }

  // g(a);
}

int32_t main() {
  ios_base::sync_with_stdio(0);cin.tie(NULL);
  int t=1;
  #ifdef DBG
  freopen("inp1.txt", "r", stdin);
  freopen("out.txt", "w", stdout);
  cin>>t;
  #endif
  while (t--) {
    solve();
    cout << endl;
  }
  return 0;
}

Compilation message (stderr)

xoranges.cpp: In function 'int32_t main()':
xoranges.cpp:91:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   91 |   freopen("inp1.txt", "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
xoranges.cpp:92:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   92 |   freopen("out.txt", "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 12
• Subtask 2: 0 / 18
• Subtask 3: 0 / 25
• Subtask 4: 0 / 20
• Subtask 5: 0 / 25