Submission #715669

#	Time	Username	Problem	Language	Result	Execution time	Memory
715669		ParsaS	Furniture (JOI20_furniture)	C++17	100 / 100	371 ms	5452 KiB

furniture

// In the name of God
//        : )
#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define fi first
#define se second
#define mp make_pair
typedef long long ll;
const int N = 1000 + 5;
bool di[2] = {0, 1}, dj[2] = {1, 0};
int n, m;
bool grid[N][N], ok[2][N][N];
int cnt[N * 2];

bool valid(int i, int j) {
    return i >= 0 && j >= 0 && i < n && j < m && grid[i][j] == 0;
}

void dfs(int s, int t, int k) {
    ok[k == -1][s][t] = true;
    for (int i = 0; i < 2; i++) {
        int x = s + k * di[i], y = t + dj[i] * k;
        if (valid(x, y) && !ok[k == -1][x][y]) {
            dfs(x, y, k);
        }
    }
}
void upd(int i, int j, int k) {
    bool tmp = false;
    for (int t = 0; t < 2; t++) {
        tmp |= valid(i - k * di[t], j - k * dj[t]) && ok[k == -1][i - k * di[t]][j - k * dj[t]];
    }
    if (tmp)
        return;
    if (ok[0][i][j] && ok[1][i][j])
        cnt[i + j]--;
    ok[k == -1][i][j] = false;
    for (int t = 0; t < 2; t++) {
        int x = i + di[t] * k, y = j + dj[t] * k;
        if (valid(x, y) && ok[k == -1][x][y])
            upd(x, y, k);
    }
}

void solve() {
    cin >> n >> m;
    for (int i = 0; i < n; i++)
        for (int j = 0; j < m; j++)
            cin >> grid[i][j];

    dfs(0, 0, 1);
    dfs(n - 1, m - 1, -1);
    for (int i = 0; i < n; i++)
        for (int j = 0; j < m; j++)
            cnt[i + j] += ok[0][i][j] && ok[1][i][j];
    int q; cin >> q;
    while (q--) {
        int i, j; cin >> i >> j;
        i--, j--;
        if (!ok[0][i][j] || !ok[1][i][j]) {
            cout << 1 << '\n';
            grid[i][j] = 1;
        }
        else if (cnt[i + j] > 1) {
            cout << 1 << '\n';
            grid[i][j] = 1;
            ok[0][i][j] = ok[1][i][j] = false;
            cnt[i + j]--;
            for (int t = 0; t < 2; t++) {
                int x = i + di[t], y = j + dj[t];
                int x2 = i - di[t], y2 = j - dj[t];
                if (valid(x, y) && ok[0][x][y])
                    upd(i + di[t], j + dj[t], 1);
                if (valid(x2, y2) && ok[1][x2][y2])
                    upd(i - di[t], j - dj[t], -1);
            }
        }
        else {
            cout << 0 << '\n';
        }
    }
}

int32_t main() {
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    solve();
    return 0;
}

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