Submission #769554

#	Time	Username	Problem	Language	Result	Execution time	Memory
769554		danikoynov	Maze (JOI23_ho_t3)	C++14	100 / 100	1680 ms	634860 KiB

Main

#include<bits/stdc++.h>
#define endl '\n'

using namespace std;
typedef long long ll;

void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}

const int maxn = 6e6 + 10, block = sqrt(maxn) + 10;

struct cell
{
    int x, y;

    cell(int _x = 0, int _y = 0)
    {
        x = _x;
        y = _y;
    }

    cell add(const cell &r) const
    {
        cell d;
        d.x = x + r.x;
        d.y = y + r.y;
        return d;
    }
};

cell neib[4] = {{0, 1}, {1, 0}, {-1, 0}, {0, -1}};

int n, m, h;

vector < int > a[block], tr[block], tl[block];
vector < int > tu[block], td[block];
vector < int > ver_idx[block];

int stx, sty, enx, eny;

int nxt;

int dist[5 * maxn];
int is_div[maxn];
void add_edges_row(int row, int i, int j, int ver, vector < int > &vec)
{
    if (j - i + 1 == 2 * h - 1)
    {
        vec.push_back(tr[row][i]);
        vec.push_back(tl[row][j]);
    }
    else
    {
        if (i == 1)
            vec.push_back(tl[row][j]);
        else
        {
            int to = i;
            if (!is_div[i])
                to = 2 * h - 1 - i % (2 * h - 1) + i;
            if (to >= j)
                vec.push_back(tr[row][i]);
            else
            {
                vec.push_back(tr[row][i]);
                vec.push_back(tl[row][j]);
            }
        }
    }
}



void add_edges_col(int col, int i, int j, int ver, vector < int > &vec)
{
    if (j - i + 1 == 2 * h - 1)
    {
        vec.push_back(td[i][col]);
        vec.push_back(tu[j][col]);
    }
    else
    {
        if (i == 1)
            vec.push_back(tu[j][col]);
        else
        {
            int to = i;
            if (!is_div[i])
                to = 2 * h - 1 - i % (2 * h - 1) + i;
            if (to >= j)
                vec.push_back(td[i][col]);
            else
            {
                vec.push_back(td[i][col]);
                vec.push_back(tu[j][col]);
            }
        }
    }
}

int type[5 * maxn];
pair < int, int > cor[5 * maxn];
void solve()
{
    cin >> n >> m >> h;
    cin >> stx >> sty;
    cin >> enx >> eny;
    for (int i = 0; i <= max(n, m); i ++)
    {
        if (i % (2 * h - 1) == 0)
            is_div[i] = 1;
    }
    for (int i = 1; i <= n; i ++)
    {
        a[i].resize(m + 2);
        tl[i].resize(m + 2);
        tr[i].resize(m + 2);
        td[i].resize(m + 2);
        tu[i].resize(m + 2);
        ver_idx[i].resize(m + 2);

        string s;
        cin >> s;
        char c;
        for (int j = 1; j <= m; j ++)
        {
            c = s[j - 1];
            if (c == '.')
                a[i][j] = 0;
            else
                a[i][j] = 1;
        }
    }

    int cnt = 0;
    nxt = n * m;
    for (int i = 1; i <= n; i ++)
    {
        for (int j = 1; j <= m; j ++)
        {
            ver_idx[i][j] = ++ cnt;
        }
    }

    for (int i = 1; i <= n; i ++)
    {
        for (int j = 1; j <= m; j ++)
        {
            tr[i][j] = ++ nxt;
            type[nxt] = 1;
            cor[nxt] = {i, j};
            tl[i][j] = ++ nxt;
            type[nxt] = 2;
            cor[nxt] = {i, j};
        }

    }

    for (int j = 1; j <= m; j ++)
    {
        for (int i = 1; i <= n; i ++)
        {
            tu[i][j] = ++ nxt;
            type[nxt] = 4;
            cor[nxt] = {i, j};
            td[i][j] = ++ nxt;
            type[nxt] = 3;
            cor[nxt] = {i, j};

        }
    }



    for (int i = 1; i <= nxt; i ++)
        dist[i] = 1e9;

    deque < int > dq;
    dq.push_back(ver_idx[stx][sty]);
    dist[ver_idx[stx][sty]] = 0;
    vector < int > sus;
    while(!dq.empty())
    {
        int cur = dq.front();
        dq.pop_front();
        if (cur == ver_idx[enx][eny])
        {
            cout << dist[cur] << endl;
            return;
        }
        if (cur <= n * m)
        {
            cell c(cur / m + 1, cur % m);
            if (cur % m == 0)
                c.x --, c.y = m;

            for (int i = 0; i < 4; i ++)
            {
                cell nb = neib[i].add(c);
                if (nb.x == 0 || nb.x == n + 1 || nb.y == 0 || nb.y == m + 1 || a[nb.x][nb.y] == 1)
                    continue;
                int u = ver_idx[nb.x][nb.y];
                int w = 0;
                if (dist[u] > dist[cur] + w)
                {
                    dist[u] = dist[cur] + w;
                    if (w == 0)
                        dq.push_front(u);
                    else
                        dq.push_back(u);
                }
            }
            int i = c.x;
            int j = c.y;
            sus.clear();

            int st_row = max(1, i - h), en_row = min(n, i + h);
            int st_col = max(1, j - h), en_col = min(m, j + h);
            int fs_row = st_row, ds_row = en_row;
            if (fs_row == i - h)
                fs_row ++;
            if (ds_row == i + h)
                ds_row --;

            bool f1 = false, f2 = false;
            if (st_row == i - h)
            {
                if (st_col == j - h)
                    st_col ++, f1 = true;
                if (en_col == j + h)
                    en_col --, f2 = true;
            }
            add_edges_row(st_row, st_col, en_col, ver_idx[i][j], sus);
            if (st_row == i - h)
            {
                if (f1)
                    st_col --;
                if (f2)
                    en_col ++;
            }


            f1 = f2 = false;
            if (en_row == i + h)
            {
                if (st_col == j - h)
                    st_col ++, f1 = true;
                if (en_col == j + h)
                    en_col --, f2 = true;
            }

            add_edges_row(en_row, st_col, en_col, ver_idx[i][j], sus);

            if (en_row == i + h)
            {
                if (f1)
                    st_col --;
                if (f2)
                    en_col ++;
            }



            f1 = f2 = false;
            if (st_col == j - h)
            {
                if (st_row == i - h)
                    st_row ++, f1 = true;
                if (en_row == i + h)
                    en_row --, f2 = true;
            }

            add_edges_col(st_col, st_row, en_row, ver_idx[i][j], sus);
            if (st_col == j - h)
            {
                if (f1)
                    st_row --;
                if (f2)
                    en_row ++;
            }

            /// right col
            f1 = f2 = false;
            if (en_col == j + h)
            {
                if (st_row == i - h)
                    st_row ++, f1 = true;
                if (en_row == i + h)
                    en_row --, f2 = true;
            }

            add_edges_col(en_col, st_row, en_row, ver_idx[i][j], sus);
            if (en_col == j + h)
            {
                if (f1)
                    st_row --;
                if (f2)
                    en_row ++;
            }

            for (int u : sus)
            {
                if (dist[u] > dist[cur] + 1)
                {
                    dist[u] = dist[cur] + 1;
                    dq.push_back(u);
                }
            }
        }
        if (type[cur] == 1)
        {
            int x = cor[cur].first, y = cor[cur].second;
            if (y != m && !is_div[y])
            {
                if (dist[tr[x][y + 1]] > dist[cur])
                {
                    dist[tr[x][y + 1]] = dist[cur];
                    dq.push_front(tr[x][y + 1]);
                }
            }
            if (dist[ver_idx[x][y]] > dist[cur])
            {
                dist[ver_idx[x][y]] = dist[cur];
                dq.push_front(ver_idx[x][y]);
            }
        }
        if (type[cur] == 2)
        {
            int x = cor[cur].first, y = cor[cur].second;
            if (!is_div[y - 1])
            {
                if (dist[tl[x][y - 1]] > dist[cur])
                {
                    dist[tl[x][y - 1]] = dist[cur];
                    dq.push_front(tl[x][y - 1]);
                }
            }
            if (dist[ver_idx[x][y]] > dist[cur])
            {
                dist[ver_idx[x][y]] = dist[cur];
                dq.push_front(ver_idx[x][y]);
            }
        }

        if (type[cur] == 3)
        {
            int x = cor[cur].first, y = cor[cur].second;
            if (x != n && !is_div[x])
            {
                if (dist[td[x + 1][y]] > dist[cur])
                {
                    dist[td[x + 1][y]] = dist[cur];
                    dq.push_front(td[x + 1][y]);
                }
            }
            if (dist[ver_idx[x][y]] > dist[cur])
            {
                dist[ver_idx[x][y]] = dist[cur];
                dq.push_front(ver_idx[x][y]);
            }
        }
        if (type[cur] == 4)
        {
            int x = cor[cur].first, y = cor[cur].second;
            if (!is_div[x - 1])
            {
                if (dist[tu[x - 1][y]] > dist[cur])
                {
                    dist[tu[x - 1][y]] = dist[cur];
                    dq.push_front(tu[x - 1][y]);
                }
            }
            if (dist[ver_idx[x][y]] > dist[cur])
            {
                dist[ver_idx[x][y]] = dist[cur];
                dq.push_front(ver_idx[x][y]);
            }
        }

    }
    /**for (int i = 1; i <= n; i ++, cout << endl)
        for (int j = 1; j <= m; j ++)
            cout << dist[ver_idx[i][j]] << " ";*/

    int ans = dist[ver_idx[enx][eny]];
    for (int i = 1; i <= n; i ++)
        for (int j = 1; j <= m; j ++)
        {
            if (abs(i - enx) <= h && abs(j - eny) <= h)
            {
                if (abs(i - enx) + abs(j - eny) != 2 * h)
                {
                    ans = min(ans, dist[ver_idx[i][j]] + 1);
                }
            }
        }
    cout << ans << endl;


}

int main()
{
    ///freopen("test.txt", "r", stdin);
    speed();
    solve();
    return 0;
}
/**
3 3 2
1 1
3 3
.#.
##.
...
*/

• Subtask 1: 8 / 8
• Subtask 2: 19 / 19
• Subtask 3: 16 / 16
• Subtask 4: 19 / 19
• Subtask 5: 5 / 5
• Subtask 6: 19 / 19
• Subtask 7: 8 / 8
• Subtask 8: 6 / 6