Submission #1149214

#	Time	Username	Problem	Language	Result	Execution time	Memory
1149214		sh3lan	XOR (IZhO12_xor)	C++20	0 / 100	1 ms	320 KiB

xor

#include <bits/stdc++.h>
using namespace std;
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
// find_by_order, order_of_key
#define all(v) v.begin(), v.end()
#define ll long long
#define en cout << endl;
#define memo(arr, val) memset(arr, val, sizeof(arr))
#define int long long
#define f first
#define s second
#define sz(s) (int)(s).size()
#define rep(i, st, ed) for (int i = st; i < ed; i++)

bool valid(int i, int j, int n, int m) {
    return i < n && i >= 0 && j < m && j >= 0;
}

int inf = 1e18;

void Sh3lan() {
    ios::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(0);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    freopen("errors.txt", "w", stderr);

#endif
}

int mod = 1e9 + 7;

int mul(int a, int b) { return ((a % mod) * (b % mod)) % mod; }

int add(int a, int b) { return ((a % mod) + (b % mod)) % mod; }

int sub(int a, int b) { return ((a % mod) - (b % mod) + mod) % mod; }

int GCD(int a, int b) { return b == 0 ? a : GCD(b, a % b); }

int LCM(int a, int b) { return a / GCD(a, b) * b; }

int fast(int a, int m) {
    if (m == 0) return 1;
    int x = fast(a, m / 2);
    x = mul(x, x);
    if (m & 1) x = mul(x, a);
    return x % mod;
}

int dx[] = {1, -1, 0, 0, 1, -1, 1, -1};
int dy[] = {0, 0, 1, -1, 1, -1, -1, 1};
const int N = 2e3 + 5;

struct Node {
    int ch[2] = {};
    int sz = 0;
    int &operator[](int i) { return ch[i]; }
};


struct Trie {
    vector<Node> trie;

    Trie() {
        newNode();
    }

    int newNode() {
        trie.emplace_back();
        return trie.size() - 1;
    }

    void update(int x, int op) {
        int cur = 0;
        for (int i = 30; i >= 0; i--) {
            int bit = (x >> i & 1);
            if (trie[cur][bit] == 0) {
                trie[cur][bit] = newNode();
            }
            cur = trie[cur][bit];
            trie[cur].sz += op;
        }
    }

    int size(int c) {
        return trie[c].sz;
    }

    int query(int &x,int mid) {
        int cur = 0, res = 0;
        for (int i = 20; ~i; i--) {
            int bit = x >> i & 1;
            int mid_bit = mid >> i & 1;
            int xr = bit ^ mid_bit;
            if (mid_bit) {
                res += size(trie[cur][bit]);
            }
            if (size(trie[cur][xr])) {
                cur = trie[cur][xr];
            } else {
                return res;
            }
        }
        return res + size(cur);
    }
};

void solve() {
    int n, x;
    cin >> n >> x;
    vector<int> a(n);
    Trie t;
    vector<int> prf(n + 1);
    for (auto i = 0; i < n; i++) {
        cin >> a[i];
        t.update(a[i], 1);
        // prf[i + 1] = prf[i] ^ a[i];
    }

    int mx = 0, idx = -1;
    for (int i = 0; i < n; i++) {
        t.update(a[i], -1);
        int cur = t.query(a[i], x);
        if (cur > mx) {
            mx = cur;
            idx = i + 2;
        }
        t.update(prf[i], -1);
    }
    cout << idx << " " << mx << endl;
}

signed main() {
    Sh3lan();
    int t = 1;
    // cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}

Compilation message (stderr)

xor.cpp: In function 'void Sh3lan()':
xor.cpp:32:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
xor.cpp:33:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
xor.cpp:34:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |     freopen("errors.txt", "w", stderr);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100