Submission #797912

#	Time	Username	Problem	Language	Result	Execution time	Memory
797912		finn__	L-triominoes (CEOI21_ltriominoes)	C++17	10 / 100	1361 ms	468 KiB

ltrominoes

#include <bits/stdc++.h>
using namespace std;

constexpr size_t W = 13, K = 250;

pair<size_t, size_t> p[K];
bitset<1 << W> state[2];

void find_transitions(uint32_t i, uint32_t j, size_t w, bitset<1 << W> &next_state, size_t l = 0)
{
    if (i == (1 << w) - 1)
    {
        next_state[j] = 1;
        return;
    }

    for (size_t h = l; h < w; ++h)
        if (!(i & (1 << h)))
        {
            if (h && !(j & (1 << h)) && !(j & (1 << (h - 1))))
                find_transitions(i ^ (1 << h), j ^ (1 << h) ^ (1 << (h - 1)), w, next_state, h + 1);
            if (h + 1 < w && !(j & (1 << h)) && !(j & (1 << (h + 1))))
                find_transitions(i ^ (1 << h), j ^ (1 << h) ^ (1 << (h + 1)), w, next_state, h + 1);
            if (h + 1 < w && !(i & (1 << (h + 1))) && !(j & (1 << h)))
                find_transitions(i ^ (1 << h) ^ (1 << (h + 1)), j ^ (1 << h), w, next_state, h + 2);
            if (h + 1 < w && !(i & (1 << (h + 1))) && !(j & (1 << (h + 1))))
                find_transitions(i ^ (1 << h) ^ (1 << (h + 1)), j ^ (1 << (h + 1)), w, next_state, h + 2);
            break;
        }
}

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

    size_t w, h, k;
    cin >> w >> h >> k;
    assert(h <= 1000);

    for (size_t i = 0; i < k; ++i)
        cin >> p[i].first >> p[i].second, --p[i].first, --p[i].second;

    sort(p, p + k, [](auto const &a, auto const &b)
         { return a.second < b.second; });
    size_t i = 0, pos = 0;
    if (k && !p[0].second)
    {
        size_t x = 0;
        while (i < k && !p[i].second)
            x |= 1ULL << p[i].first, ++i;
        state[0][x] = 1;
    }
    else
        state[0][0] = 1;

    while (i < k)
    {
        while (pos < p[i].second)
        {
            state[1].reset();
            for (size_t i = 0; i < 1 << w; ++i)
                if (state[0][i])
                    find_transitions(i, 0, w, state[1]);
            swap(state[0], state[1]);
            ++pos;
        }

        size_t x = 0;
        size_t j = i;
        while (j < k && p[j].second == p[i].second)
            x |= 1ULL << p[j].first, ++j;
        i = j;

        state[1].reset();
        for (size_t i = 0; i < 1 << w; ++i)
            if (!(i & x) && state[0][i])
                state[1][i ^ x] = 1;
        swap(state[0], state[1]);
    }

    while (pos < h - 1)
    {
        state[1].reset();
        for (size_t i = 0; i < 1 << w; ++i)
            if (state[0][i])
                find_transitions(i, 0, w, state[1]);
        swap(state[0], state[1]);
        ++pos;
    }

    cout << (state[0][(1 << w) - 1] ? "YES" : "NO") << '\n';
}

Compilation message (stderr)

ltrominoes.cpp: In function 'void find_transitions(uint32_t, uint32_t, size_t, std::bitset<8192>&, size_t)':
ltrominoes.cpp:11:11: warning: comparison of integer expressions of different signedness: 'uint32_t' {aka 'unsigned int'} and 'int' [-Wsign-compare]
   11 |     if (i == (1 << w) - 1)
      |         ~~^~~~~~~~~~~~~~~
ltrominoes.cpp: In function 'int main()':
ltrominoes.cpp:62:34: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   62 |             for (size_t i = 0; i < 1 << w; ++i)
      |                                ~~^~~~~~~~
ltrominoes.cpp:76:30: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   76 |         for (size_t i = 0; i < 1 << w; ++i)
      |                            ~~^~~~~~~~
ltrominoes.cpp:85:30: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   85 |         for (size_t i = 0; i < 1 << w; ++i)
      |                            ~~^~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 7
• Subtask 3: 0 / 11
• Subtask 4: 0 / 17
• Subtask 5: 0 / 35
• Subtask 6: 0 / 20