Submission #1299680

#	Time	Username	Problem	Language	Result	Execution time	Memory
1299680		daotuankhoi	XOR (IZhO12_xor)	C++20	0 / 100	89 ms	25532 KiB

xor

#include <bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define ll long long

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

template <class T> bool ckmax(T &a, T b) { return a < b ? (a = b, true) : false; }
template <class T> bool ckmin(T &a, T b) { return a > b ? (a = b, true) : false; }

struct Node {   
    int id = 1e5, nxt[2];
    Node() {
        memset(nxt, 0, sizeof nxt);
    }
};

vector<Node> trie(1);

int a[250005];

void add(int x, int pos) {
    int node = 0;
    for (int i = 30; i >= 0; i--) {
        int b = x >> i & 1;
        if (trie[node].nxt[b] == 0) {
            trie[node].nxt[b] = trie.size();
            trie.emplace_back();
        }
        node = trie[node].nxt[b];
        ckmin(trie[node].id, pos);
    }
}

int get(int x, int lim) {
    int ans = 1e5, node = 0;
    for (int i = 30; i >= 0; i--) {
        int bx = x >> i & 1;
        int bl = lim >> i & 1;
        /// val ^ x > lim
        if (bl == 0 && trie[node].nxt[bx ^ 1]) {
            ckmin(ans, trie[trie[node].nxt[bx ^ 1]].id);
        }
        /// val ^ x = lim
        if (trie[node].nxt[bl ^ bx]) {
            node = trie[node].nxt[bl ^ bx];
        } else {
            return ans;
        }
    }
    ckmin(ans, trie[node].id);
    return ans;
}

int main() {
    #define NAME "test"
    if (fopen(NAME".inp", "r")) {
        freopen(NAME".inp", "r", stdin);
        freopen(NAME".out", "w", stdout);
    }
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n, x; cin >> n >> x;
    int ans = 0, pos = 0;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        a[i] ^= a[i - 1];
        add(a[i - 1], i - 1);
        int p = get(a[i], x);
        if (ckmax(ans, i - p)) pos = p;
    }
    cout << pos + 1 << ' ' << ans << '\n';
    return 0;
}

Compilation message (stderr)

xor.cpp: In function 'int main()':
xor.cpp:65:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |         freopen(NAME".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
xor.cpp:66:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |         freopen(NAME".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100