Submission #306809

#	Time	Username	Problem	Language	Result	Execution time	Memory
306809		MrDomino	Furniture (JOI20_furniture)	C++14	100 / 100	300 ms	25892 KiB

furniture

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

const int N = 2000 + 7;
int n;
int m;
int a[N][N];
bool down[N][N];
bool up[N][N];
bool on[N][N];
int cnt[2 * N];

void init()
{
    for (int i = 1; i <= n + m; i++)
    {
        cnt[i] = 0;
    }
    down[n + 1][m] = 1;
    up[1][0] = 1;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= m; j++)
        {
            if (a[i][j] == 0)
            {
                up[i][j] = up[i - 1][j] | up[i][j - 1];
            }
            else
            {
                up[i][j] = 0;
            }
        }
    }
    for (int i = n; i >= 1; i--)
    {
        for (int j = m; j >= 1; j--)
        {
            if (a[i][j] == 0)
            {
                down[i][j] = down[i + 1][j] | down[i][j + 1];
            }
            else
            {
                down[i][j] = 0;
            }
        }
    }
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= m; j++)
        {
            if (up[i][j] && down[i][j])
            {
                cnt[i + j]++;
                on[i][j] = 1;
            }
            else
            {
                on[i][j] = 0;
            }
        }
    }
}

bool bdown(int r, int c)
{
    return (on[r][c] == 1 && on[r + 1][c] == 0 && on[r][c + 1] == 0);
}

bool bup(int r, int c)
{
    return (on[r][c] == 1 && on[r - 1][c] == 0 && on[r][c - 1] == 0);
}

void dfs_up(int r, int c)
{
    if (on[r][c])
    {
        on[r][c] = 0;
        cnt[r + c]--;
    }
    if (bdown(r - 1, c))
    {
        dfs_up(r - 1, c);
    }
    if (bdown(r, c - 1))
    {
        dfs_up(r, c - 1);
    }
}

void dfs_down(int r, int c)
{
    if (on[r][c])
    {
        on[r][c] = 0;
        cnt[r + c]--;
    }
    if (bup(r + 1, c))
    {
        dfs_down(r + 1, c);
    }
    if (bup(r, c + 1))
    {
        dfs_down(r, c + 1);
    }
}

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

    cin >> n >> m;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= m; j++)
        {
            cin >> a[i][j];
        }
    }
    init();
    int q;
    cin >> q;
    while (q--)
    {
        int r, c;
        cin >> r >> c;
        if (on[r][c] == 0)
        {
            cout << "1\n";
            continue;
        }
        if (cnt[r + c] == 1)
        {
            cout << "0\n";
            continue;
        }
        cout << "1\n";
        a[r][c] = 1;
        dfs_up(r, c);
        dfs_down(r, c);
    }
}

• Subtask 1: 5 / 5
• Subtask 2: 95 / 95