Submission #1276561

#	Time	Username	Problem	Language	Result	Execution time	Memory
1276561		MinhKien	XOR (IZhO12_xor)	C++20	0 / 100	88 ms	1880 KiB

xor

#include <iostream>

using namespace std;

const int N = 2e5 + 10;
const int LG = 30;

int n, x, a[N];

struct Trie {
    struct node {
        node *child[2];

        node () {
            child[0] = child[1] = nullptr;
        }
    };

    node *root;
    Trie () {root = new node();}

    void DFS(node *cur) {
        for (int i = 0; i <= 1; ++i) {
            if (cur->child[i]) DFS(cur->child[i]);
        }
        delete(cur);
    }

    void reset() {
        DFS(root);
        root = new node();
    }

    void add(int u) {
        node *cur = root;
        for (int i = LG; i >= 0; --i) {
            int c = u >> i & 1;
            if (!cur->child[c]) cur->child[c] = new node();
            cur = cur->child[c];
        }
    }

    int Max(int u) {
        int res = 0;
        node *cur = root;
        
        for (int i = LG; i >= 0; --i) {
            int c = u >> i & 1;

            if (cur->child[c ^ 1]) {
                res |= (1 << i);
                cur = cur->child[c ^ 1];
            } else {
                cur = cur->child[c];
            }
        }

        return res;
    }
} T;

int check(int val) {
    int mx = 0, I = 0;
    for (int i = n - val + 1; i >= 1; --i) {
        T.add(a[i + val]);
        int cur = T.Max(a[i]);
        if (cur > mx) {
            mx = cur;
            I = i;
        }
    }
    T.reset();
    if (mx >= x) return I;
    return 0;
}

int main() {
    cin.tie(0); cout.tie(0);
    ios_base::sync_with_stdio(false);

    cin >> n >> x;
    for (int i = 1; i <= n; ++i) cin >> a[i];
    for (int i = n; i >= 1; --i) a[i] ^= a[i + 1];

    int l = 1, r = n, ans = -1;
    while (l <= r) {
        int mid = (l + r) >> 1;

        if (check(mid)) {
            ans = mid;
            l = mid + 1;
        } else {
            r = mid - 1;
        }
    }

    if (ans == -1) cout << ans << "\n";
    else {
        cout << check(ans) << " ";
        cout << ans << "\n";
    }

    return 0;
}

• Subtask 1: 0 / 100