Submission #769533

#	Time	Username	Problem	Language	Result	Execution time	Memory
769533		danikoynov	Maze (JOI23_ho_t3)	C++14	0 / 100	418 ms	781568 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];

vector < pair < int, bool > > adj[3 * maxn];

int stx, sty, enx, eny;

int nxt;

int visit[3 * maxn], dist[3 * maxn];

void add_edges_row(int row, int i, int j, int ver)
{
    if (j - i + 1 == 2 * h - 1)
    {
        adj[ver].push_back({tr[row][i], 1});
        adj[ver].push_back({tl[row][j], 1});
    }
    else
    {
        if (i == 1)
            adj[ver].push_back({tl[row][j], 1});
        else
        {
            int to = i;
            if (i % (2 * h - 1) != 0)
                to = 2 * h - 1 - i % (2 * h - 1) + i;
            if (to >= j)
                adj[ver].push_back({tr[row][i], 1});
            else
            {
                adj[ver].push_back({tr[row][i], 1});
                adj[ver].push_back({tl[row][j], 1});
            }
        }
    }
}

void add_edges_col(int col, int i, int j, int ver)
{
    if (j - i + 1 == 2 * h - 1)
    {
        adj[ver].push_back({td[i][col], 1});
        adj[ver].push_back({tu[j][col], 1});
    }
    else
    {
        if (i == 1)
            adj[ver].push_back({tu[j][col], 1});
        else
        {
            int to = i;
            if (i % (2 * h - 1) != 0)
                to = 2 * h - 1 - i % (2 * h - 1) + i;
            if (to >= j)
                adj[ver].push_back({td[i][col], 1});
            else
            {
                adj[ver].push_back({td[i][col], 1});
                adj[ver].push_back({tu[j][col], 1});
            }
        }
    }
}

int is_div[maxn];
void solve()
{
    cin >> n >> m >> h;
    cin >> stx >> sty;
    cin >> enx >> eny;
    for (int i = 1; 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;
            tl[i][j] = ++ nxt;
        }
        for (int j = 1; j <= m; j ++)
        {
            if (!is_div[j] && j != m)
                adj[tr[i][j]].push_back({tr[i][j + 1], 0});
            adj[tr[i][j]].push_back({ver_idx[i][j], 0});

            if (!is_div[j - 1])
                adj[tl[i][j]].push_back({tl[i][j - 1], 0});
            adj[tl[i][j]].push_back({ver_idx[i][j], 0});
        }
    }

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

        for (int i = 1; i <= n; i ++)
        {
            if (!is_div[i] && i != n)
                adj[td[i][j]].push_back({td[i + 1][j], 0});
            adj[td[i][j]].push_back({ver_idx[i][j], 0});

            if (!is_div[i - 1])
                adj[tu[i][j]].push_back({tu[i - 1][j], 0});
            adj[tu[i][j]].push_back({ver_idx[i][j], 0});
        }
    }

    ///exit(0);
    for (int i = 1; i <= n; i ++)
        for (int j = 1; j <= m; j ++)
        {
            cell cur(i, j);
            for (int d = 0; d < 4; d ++)
            {
                cell nb = cur.add(neib[d]);
                if (nb.x > 0 && nb.x <= n && nb.y > 0 && nb.y <= m)
                    if (a[nb.x][nb.y] == 0)
                    {
                        adj[ver_idx[cur.x][cur.y]].push_back({ver_idx[nb.x][nb.y], 0});
                    }
            }


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



            /// down row
            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;
            }
            ////cout << i << " " << j << " range " << st_col << " " << en_col << endl;
            ///add_edges(row_root[en_row], 1, m, st_col, en_col, ver_idx[i][j], 1);
            add_edges_row(en_row, st_col, en_col, ver_idx[i][j]);

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


            /// left 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_root[st_col], 1, n, st_row, en_row, ver_idx[i][j], 1);
            add_edges_col(st_col, st_row, en_row, ver_idx[i][j]);
            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;
            }
            ///cout << i << " " << j << " " << "range " << st_row << " " << en_row << " col " << en_col << endl;
            ///add_edges(col_root[en_col], 1, n, st_row, en_row, ver_idx[i][j], 1);
            add_edges_col(en_col, st_row, en_row, ver_idx[i][j]);
            if (en_col == j + h)
            {
                if (f1)
                    st_row --;
                if (f2)
                    en_row ++;
            }
            /**for (int row = st_row; row <= en_row; row ++)
            {
                if (row == i - h || row == i + h)
                {
                    st_col ++, en_col --;

                    add_edges(row_root[row], 1, m, st_col, en_col, ver_idx[i][j], 1);
                    st_col --, en_col ++;
                }
                else
                {
                    adj[ver_idx[cur.x][cur.y]].push_back({fict[row][cur.y], 1});
                }
            }*/

        }


    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;
    while(!dq.empty())
    {
        int cur = dq.front();
        dq.pop_front();
        if (cur == ver_idx[enx][eny])
        {
            cout << dist[cur] << endl;
            return;
        }
        for (pair < int, int > nb : adj[cur])
        {
            int u = nb.first;
            int w = nb.second;
            if (dist[u] > dist[cur] + w)
            {
                dist[u] = dist[cur] + w;
                if (w == 0)
                    dq.push_front(u);
                else
                    dq.push_back(u);
            }
        }
    }
    /**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: 0 / 8
• Subtask 2: 0 / 19
• Subtask 3: 0 / 16
• Subtask 4: 0 / 19
• Subtask 5: 0 / 5
• Subtask 6: 0 / 19
• Subtask 7: 0 / 8
• Subtask 8: 0 / 6