Submission #800554

#	Time	Username	Problem	Language	Result	Execution time	Memory
800554		Johann	L-triominoes (CEOI21_ltriominoes)	C++14	17 / 100	2277 ms	67104 KiB

ltrominoes

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

typedef long long ll;
typedef vector<bool> vb;
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef vector<pii> vpii;
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()

const int maxW = 13;
int W, H, K;
map<int, int> blocked;
typedef bitset<1 << maxW> bs;
typedef vector<bs> vbs;
typedef vector<vbs> vvbs;
bs dp[2];
bs mat[1 << maxW];
vvbs lift;
vvbs mod;

void dfs(int idx, int base, int next, bs &nextdp)
{
    if (idx == W)
    {
        nextdp[next] = true;
        return;
    }
    if (base & (1 << idx))
        dfs(idx + 1, base, next, nextdp);
    else
    {
        // _X my pos: 1 << idx

        // TT
        // _T
        if (idx < W - 1 && ((3 << idx) & next) == 0)
            dfs(idx + 1, base | (1 << idx), next | (3 << idx), nextdp);

        // _TT
        // _T_
        if (idx > 0 && ((3 << (idx - 1)) & next) == 0)
            dfs(idx + 1, base | (1 << idx), next | (3 << (idx - 1)), nextdp);

        // T_
        // TT
        if (idx < W - 1 && (base & (3 << idx)) == 0 && (next & (2 << idx)) == 0)
            dfs(idx + 2, base | (3 << idx), next | (2 << idx), nextdp);

        // _T
        // TT
        if (idx < W - 1 && (base & (3 << idx)) == 0 && (next & (1 << idx)) == 0)
            dfs(idx + 2, base | (3 << idx), next | (1 << idx), nextdp);
    }
}

void mul(bs &base, int liftidx, bs &re, int block = 0)
{
    re = 0;
    for (int j = 0; j < 1 << W; ++j)
    {
        if (!base[j])
            continue;
        if (j & block)
            continue;

        re |= lift[liftidx][j | block];
    }
}

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

    cin >> W >> H >> K;
    for (int k = 0, x, y; k < K; ++k)
    {
        cin >> x >> y;
        --x, --y;
        blocked[y] = blocked[y] | (1 << x);
    }

    lift.assign(4, vbs(1 << W));
    for (int i = 0; i < 1 << W; ++i)
        dfs(0, i, 0, lift[0][i]);

    for (int j = 1; j < sz(lift); ++j)
        for (int i = 0; i < 1 << W; ++i)
            mul(lift[j - 1][i], j - 1, lift[j][i]);

    assert(W < 13);

    mod.assign(1 << W, vbs(3));
    for (int i = 0; i < (1 << W); ++i)
    {
        mul(lift[3][i], 2, mod[i][0]);
        mul(mod[i][0], 0, mod[i][1]);
        mul(mod[i][1], 0, mod[i][2]);
    }

    assert(W < 13);

    if (false)
    {
        dp[0] = 0;
        dp[0][0] = true;
        for (int i = 0; i < H; ++i)
        {
            int ii = i & 1;
            int ni = ii ^ 1;
            dp[ni] = 0;

            mul(dp[ii], 0, dp[ni], blocked[i]);
        }

        if (dp[H & 1][0])
            cout << "YES\n";
        else
            cout << "NO\n";
    }
    else
    {
        bs start = 0, tmp;
        start[0] = 1;
        blocked[H - 1] = blocked[H - 1] | 0;
        int h = 0;
        for (pii p : blocked)
        {
            int delta = p.first - h;
            if (delta >= 11)
            {
                tmp = 0;
                for (int i = 0; i < (1 << W); ++i)
                    if (start[i])
                        tmp |= mod[i][delta % 3];
                swap(tmp, start);
                h = p.first;
            }
            else
            {
                for (int j = sz(lift) - 1; j >= 0; --j)
                {
                    if (p.first - h >= (1 << j))
                    {
                        h += (1 << j);
                        mul(start, j, tmp);
                        swap(start, tmp);
                    }
                }
                assert(p.first == h);
            }
            mul(start, 0, tmp, p.second);
            swap(start, tmp);
            ++h;
        }

        if (start[0])
            cout << "YES\n";
        else
            cout << "NO\n";
    }

    return 0;
}

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