Submission #1092412

#	Time	Username	Problem	Language	Result	Execution time	Memory
1092412		juicy	XOR (IZhO12_xor)	C++17	100 / 100	1568 ms	24664 KiB

xor

#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

const int N = 25e4 + 5, M = 7500005, LG = 30;

int n, k, node = 1;
int a[N], nxt[M][2], lst[M];

void reset() {
  while (node) {
    nxt[node][0] = nxt[node][1] = lst[node] = 0;
    --node;
  }
  node = 1;
}

void add(int x, int i) {
  int p = 1;
  for (int j = LG - 1; ~j; --j) {
    int c = x >> j & 1;
    if (!nxt[p][c]) {
      nxt[p][c] = ++node;
    }
    p = nxt[p][c];
  }
  if (!lst[p]) {
    lst[p] = i;
  }
}

array<int, 2> qry(int x) {
  int m = 0, p = 1;
  for (int j = LG - 1; ~j; --j) {
    int c = x >> j & 1;
    if (nxt[p][c ^ 1]) {
      m += 1 << j;
      p = nxt[p][c ^ 1];
    } else {
      assert(nxt[p][c]);
      p = nxt[p][c];
    }
  }
  assert(lst[p]);
  return {m, lst[p]};
}

int check(int m) {
  reset();
  for (int i = 1, j = 0; i <= n; ++i) {
    while (j <= i - m) {
      add(a[j], j + 1);
      ++j;
    }
    if (i >= m) {
      auto [x, l] = qry(a[i]);
      if (x >= k) {
        return l;
      }
    }
  }
  return 0;
}

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

  cin >> n >> k;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
    a[i] ^= a[i - 1];
  }
  int l = 1, r = n, p = -1, len = -1;
  while (l <= r) {
    int m = (l + r) / 2;
    int i = check(m);
    if (i) {
      p = i;
      len = m;
      l = m + 1;
    } else {
      r = m - 1;
    }
  }
  cout << p << " " << len << "\n";
  return 0;
}

• Subtask 1: 100 / 100