Submission #812530

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
812530	2023-08-07T09:07:00 Z	piOOE	Ancient Machine 2 (JOI23_ancient2)	C++17	100 / 100	87 ms	764 KB

ancient2

#include "ancient2.h"
#include <bits/stdc++.h>

using namespace std;

namespace {
    constexpr int maxN = 1001;
    int n, Q = 0, basisSize = 0;

    bool findPrefixBit(int m) { // 0 indexed
        vector<int> a(m + 3), b(m + 3);
        for (int i = 0; i < m; ++i) {
            a[i] = b[i] = i + 1;
        }
        a[m + 1] = b[m + 1] = m + 1;
        a[m + 2] = b[m + 2] = m + 2;
        a[m] = m + 1, b[m] = m + 2;
        Q += 1;
        return Query(size(a), a, b) == m + 2;
    }

    int findLongestPrefix(const string &s, const string &t) {
        for (int len = min(size(s), size(t)); len > 0; --len) {
            if (s.substr(0, len) == t.substr(size(t) - len)) {
                return len;
            }
        }
        return 0;
    }

    bool findSuffixBit(int m, string suf) { // find m-th last bit (1 indexed, i.e. the last char is the 1st)
        suf = '1' + suf;
        vector<int> a(m + 1), b(m + 1);
        a[m] = b[m] = m;
        for (int i = 0; i <= m; ++i) {
            string sa = suf.substr(0, i) + '0';
            string sb = suf.substr(0, i) + '1';
            a[i] = findLongestPrefix(suf, sa);
            b[i] = findLongestPrefix(suf, sb);
        }
        Q += 1;
        return Query(m + 1, a, b) == m;
    }

    bitset<maxN> basis[maxN];

    int query(bitset<maxN> a) {
        for (int i = 0; i < n; ++i) {
            if (!a[i]) {
                continue;
            }
            if (basis[i].none()) {
                return -1;
            }
            a ^= basis[i];
        }
        return a[n];
    }

    bool insert(bitset<maxN> a) {
        for (int i = 0; i < n; ++i) {
            if (!a[i]) {
                continue;
            }
            if (basis[i].none()) {
                basis[i] = a;
                basisSize += 1;
                return true;
            }
            a ^= basis[i];
        }
        return false;
    }

    int findXor(int p, int q) { // finds xor of s[x] (x = q + p * k)
        int m = p * 2;
        vector<int> a(m);
        iota(a.begin(), a.end(), 1), iota(a.begin() + p, a.end(), p + 1);
        a[p - 1] = 0, a[m - 1] = p;
        vector<int> b = a;
        b[q] += p, b[q + p] -= p;
        Q += 1;
        return Query(m, a, b) >= p;
    }
}  // namespace

std::string Solve(int N) {
    n = N;
    constexpr int M = 100;
    vector<int> ans(n, -1);

    for (int i = 0; i < min(n, M); ++i) {
        ans[i] = findPrefixBit(i);
        bitset<maxN> b{};
        b[i] = 1, b[n] = ans[i];
        insert(b);
    }

    string suf;
    for (int i = n - 1; i >= max(n - M, M); --i) {
        ans[i] = findSuffixBit(n - i, suf);
        suf = char('0' + ans[i]) + suf;
        bitset<maxN> b{};
        b[i] = 1, b[n] = ans[i];
        insert(b);
    }

    mt19937 rnd(228);

    while (Q < 1000 && basisSize < n) {
        constexpr int R = 51;
        int p = rnd() % R + 1, q = rnd() % p;
        bitset<maxN> b{};
        for (int i = q; i < n; i += p) {
            b[i] = 1;
        }
        if (query(b) == -1) {
            b[n] = findXor(p, q);
            insert(b);
        }
    }

    for (int i = M; i + M < n; ++i) {
        bitset<maxN> b{};
        b[i] = 1;
        ans[i] = query(b);
    }

    string s(n, '?');
    for (int i = 0; i < n; ++i) {
        s[i] = '0' + ans[i];
    }
    return s;
}

Subtask #1

100.0 / 100.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	73 ms	428 KB	Output is correct
2	Correct	61 ms	336 KB	Output is correct
3	Correct	63 ms	432 KB	Output is correct
4	Correct	63 ms	412 KB	Output is correct
5	Correct	64 ms	412 KB	Output is correct
6	Correct	61 ms	372 KB	Output is correct
7	Correct	65 ms	488 KB	Output is correct
8	Correct	65 ms	416 KB	Output is correct
9	Correct	65 ms	420 KB	Output is correct
10	Correct	65 ms	420 KB	Output is correct
11	Correct	67 ms	364 KB	Output is correct
12	Correct	63 ms	360 KB	Output is correct
13	Correct	64 ms	472 KB	Output is correct
14	Correct	64 ms	432 KB	Output is correct
15	Correct	64 ms	400 KB	Output is correct
16	Correct	66 ms	432 KB	Output is correct
17	Correct	61 ms	432 KB	Output is correct
18	Correct	70 ms	764 KB	Output is correct
19	Correct	63 ms	428 KB	Output is correct
20	Correct	61 ms	336 KB	Output is correct
21	Correct	63 ms	352 KB	Output is correct
22	Correct	61 ms	336 KB	Output is correct
23	Correct	62 ms	508 KB	Output is correct
24	Correct	61 ms	436 KB	Output is correct
25	Correct	63 ms	464 KB	Output is correct
26	Correct	65 ms	372 KB	Output is correct
27	Correct	61 ms	348 KB	Output is correct
28	Correct	64 ms	400 KB	Output is correct
29	Correct	61 ms	420 KB	Output is correct
30	Correct	61 ms	432 KB	Output is correct
31	Correct	72 ms	348 KB	Output is correct
32	Correct	70 ms	368 KB	Output is correct
33	Correct	60 ms	428 KB	Output is correct
34	Correct	72 ms	348 KB	Output is correct
35	Correct	65 ms	340 KB	Output is correct
36	Correct	61 ms	348 KB	Output is correct
37	Correct	63 ms	428 KB	Output is correct
38	Correct	74 ms	344 KB	Output is correct
39	Correct	64 ms	348 KB	Output is correct
40	Correct	63 ms	412 KB	Output is correct
41	Correct	69 ms	368 KB	Output is correct
42	Correct	64 ms	432 KB	Output is correct
43	Correct	60 ms	356 KB	Output is correct
44	Correct	71 ms	428 KB	Output is correct
45	Correct	63 ms	400 KB	Output is correct
46	Correct	72 ms	424 KB	Output is correct
47	Correct	61 ms	352 KB	Output is correct
48	Correct	84 ms	428 KB	Output is correct
49	Correct	64 ms	420 KB	Output is correct
50	Correct	87 ms	428 KB	Output is correct
51	Correct	61 ms	428 KB	Output is correct
52	Correct	71 ms	532 KB	Output is correct
53	Correct	72 ms	396 KB	Output is correct
54	Correct	68 ms	428 KB	Output is correct
55	Correct	73 ms	348 KB	Output is correct
56	Correct	63 ms	428 KB	Output is correct
57	Correct	74 ms	432 KB	Output is correct
58	Correct	70 ms	432 KB	Output is correct
59	Correct	67 ms	428 KB	Output is correct
60	Correct	64 ms	428 KB	Output is correct
61	Correct	74 ms	356 KB	Output is correct
62	Correct	80 ms	428 KB	Output is correct
63	Correct	64 ms	432 KB	Output is correct