Submission #896606

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
896606	2024-01-01T17:40:20 Z	borisAngelov	XOR (IZhO12_xor)	C++17	100 / 100	117 ms	98168 KB

xor

#include <bits/stdc++.h>

using namespace std;

const int maxn = 250005;
const int maxBits = 29;
const int inf = 1e9;

int n, minXor;

int a[maxn];
int pref[maxn];

int result = inf;

struct Trie
{
    struct Node
    {
        int children[2];
        int minPos;

        Node()
        {
            children[0] = -1;
            children[1] = -1;
            minPos = inf;
        }
    };

    Node trie[maxn * 32];

    int root = 1;
    int nodeCnt = 1;

    void addNumber(int node, int number, int pos, int bit)
    {
        if (bit == -1)
        {
            trie[node].minPos = min(trie[node].minPos, pos);
            return;
        }

        bool hasBit = ((number & (1 << bit)) > 0);

        if (trie[node].children[hasBit] == -1)
        {
            trie[node].children[hasBit] = ++nodeCnt;
        }

        addNumber(trie[node].children[hasBit], number, pos, bit - 1);

        trie[node].minPos = inf;

        if (trie[node].children[0] != -1)
        {
            trie[node].minPos = min(trie[node].minPos, trie[trie[node].children[0]].minPos);
        }

        if (trie[node].children[1] != -1)
        {
            trie[node].minPos = min(trie[node].minPos, trie[trie[node].children[1]].minPos);
        }
    }

    void query(int node, int number, int pos, int bit, int currentXor)
    {
        if (bit == -1)
        {
            if (currentXor >= minXor)
            {
                //cout << "found " << trie[node].minPos << endl;
                result = min(result, trie[node].minPos);
            }

            return;
        }

        //cout << number << " " << pos << " " << bit << " :: " << currentXor << endl;

        if (currentXor + (1 << (bit + 1)) - 1 < minXor)
        {
            return;
        }

        bool hasBit = ((number & (1 << bit)) > 0);

        if (trie[node].children[hasBit] != -1)
        {
            query(trie[node].children[hasBit], number, pos, bit - 1, currentXor);
        }

        if (trie[node].children[1 - hasBit] != -1)
        {
            query(trie[node].children[1 - hasBit], number, pos, bit - 1, currentXor + (1 << bit));
        }
    }
};

Trie trie;

void fastIO()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}

int main()
{
    fastIO();

    cin >> n >> minXor;

    for (int i = 1; i <= n; ++i)
    {
        cin >> a[i];
    }

    trie.addNumber(1, 0, 0, maxBits);

    int ans = 0;
    int from = 0;

    for (int i = 1; i <= n; ++i)
    {
        pref[i] = (pref[i - 1] ^ a[i]);

        result = inf;
        trie.query(1, pref[i], i, maxBits, 0);

        trie.addNumber(1, pref[i], i, maxBits);

        if (result != inf)
        {
            ++result;

            if (ans < i - result + 1)
            {
                ans = i - result + 1;
                from = result;
            }
        }
    }

    cout << from << ' ' << ans << endl;

    return 0;
}

/*
4 6
6 1 2 4
4 3
6 1 2 4
*/

Subtask #1

100.0 / 100.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	21 ms	95060 KB	Output is correct
2	Correct	17 ms	94868 KB	Output is correct
3	Correct	17 ms	95064 KB	Output is correct
4	Correct	17 ms	94812 KB	Output is correct
5	Correct	23 ms	95100 KB	Output is correct
6	Correct	25 ms	95152 KB	Output is correct
7	Correct	26 ms	95068 KB	Output is correct
8	Correct	27 ms	95316 KB	Output is correct
9	Correct	52 ms	96092 KB	Output is correct
10	Correct	52 ms	96092 KB	Output is correct
11	Correct	53 ms	96092 KB	Output is correct
12	Correct	52 ms	96092 KB	Output is correct
13	Correct	52 ms	96080 KB	Output is correct
14	Correct	52 ms	96080 KB	Output is correct
15	Correct	52 ms	96176 KB	Output is correct
16	Correct	51 ms	96184 KB	Output is correct
17	Correct	110 ms	98168 KB	Output is correct
18	Correct	108 ms	98128 KB	Output is correct
19	Correct	111 ms	98128 KB	Output is correct
20	Correct	117 ms	98128 KB	Output is correct