Submission #1245303

#	Time	Username	Problem	Language	Result	Execution time	Memory
1245303		ducdev	Paint (COI20_paint)	C++20	17 / 100	3094 ms	64696 KiB

paint

// Author: 4uckd3v - Nguyen Cao Duc
#include <bits/stdc++.h>
using namespace std;

#define cell(x, y) (((x) - 1) * n + (y))

typedef long long ll;
typedef pair<int, int> ii;

const int MAX_N = 2e5;
const int MAX_Q = 1e5;
const int MOD = 1e9 + 7;
const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};

struct Query {
    int x, y, color;
    Query() {};
    Query(int x, int y, int color) : x(x), y(y), color(color) {};
};

struct DSU {
    vector<int> par, sz, lef, rig, color;
    vector<set<int>> border;
    int n;

    int findSet(int u) {
        return u == par[u] ? u : par[u] = findSet(par[u]);
    };

    int getColor(int u) {
        return color[findSet(u)];
    };

    void setColor(int u, int c) {
        color[findSet(u)] = c;
    };

    bool unionSet(int u, int v, int c) {
        u = findSet(u), v = findSet(v);

        if (u == v) return false;

        if (sz[u] < sz[v]) swap(u, v);
        if (border[u].size() < border[v].size()) border[u].swap(border[v]);
        for (int node : border[v])
            if (findSet(node) != u) border[u].insert(node);

        setColor(u, c);
        sz[u] += sz[v];
        par[v] = u;
        lef[u] = min(lef[u], lef[v]);
        rig[u] = max(rig[u], rig[v]);

        return true;
    };

    DSU() {};
    DSU(int n) : n(n) {
        par.resize(n + 1), color.resize(n + 1);
        lef.resize(n + 1), rig.resize(n + 1);
        border.resize(n + 1), sz.resize(n + 1);
        for (int u = 1; u <= n; u++) {
            par[u] = u;
            lef[u] = u, rig[u] = u;
            sz[u] = 1;
        };
    };
};

int m, n, q;
vector<Query> queries;
vector<vector<int>> a;

bool valid(int x, int y) {
    return (x >= 1 && x <= m && y >= 1 && y <= n);
};

namespace SUBTASK_1 {
    const int MN = 1e4;

    bool vis[MN + 5];
    vector<vector<int>> b;

    bool checkSubtask() {
        return m * n <= 1e4 && q <= 1e4;
    };

    void dfs(int x, int y, int color) {
        vis[cell(x, y)] = true;
        for (int i = 0; i < 4; i++) {
            int u = x + dx[i];
            int v = y + dy[i];
            if (valid(u, v) && !vis[cell(u, v)] && b[u][v] == b[x][y]) dfs(u, v, color);
        };
        b[x][y] = color;
    };

    void Solve() {
        b = a;
        for (const Query &q : queries) {
            int x = q.x, y = q.y, color = q.color;

            for (int i = 1; i <= m * n; i++) vis[i] = false;

            dfs(x, y, color);
        };
        for (int i = 1; i <= m; i++) {
            for (int j = 1; j <= n; j++) {
                cout << b[i][j] << " ";
            };
            cout << '\n';
        };
    };
};  // namespace SUBTASK_1

namespace SUBTASK_2 {
    const int M = 1;
    const int N = MAX_N;
    const int Q = MAX_Q;
    bool checkSubtask() {
        return m <= M && n <= N && q <= Q;
    };

    void Solve() {
        DSU DSU(n);
        for (int i = 1; i <= n; i++) {
            DSU.setColor(i, a[1][i]);
        };

        for (int i = 1; i < n; i++) {
            if (a[1][i] == a[1][i + 1]) {
                DSU.unionSet(i, i + 1, a[1][i]);
            };
        };

        for (const Query &q : queries) {
            int idx = q.y, color = q.color;
            if (color == DSU.getColor(idx)) continue;

            DSU.setColor(idx, color);

            int root = DSU.findSet(idx);
            int l = DSU.lef[root], r = DSU.rig[root];
            int newL = (l - 1 == 0 ? idx : DSU.findSet(l - 1));
            int newR = (r + 1 > n ? idx : DSU.findSet(r + 1));

            if (DSU.color[newL] == color) {
                DSU.unionSet(newL, idx, color);
            };
            if (DSU.color[newR] == color) {
                DSU.unionSet(newR, idx, color);
            };
        };

        for (int i = 1; i <= n; i++) cout << DSU.getColor(i) << ' ';
        cout << '\n';
    };
};  // namespace SUBTASK_2

void printMatrix(int m, int n, const vector<vector<int>> &a) {
    for (int i = 1; i <= m; i++) {
        for (int j = 1; j <= n; j++) {
            cout << a[i][j] << ' ';
        };
        cout << '\n';
    };
};

namespace SUBTASK_3 {
    const int SIZE = 2e5;

    bool checkSubtask() {
        for (Query &q : queries)
            if (q.color > 1) return false;
        return true;
    };

    vector<vector<int>> rotate(int m, int n, const vector<vector<int>> &a) {
        vector<vector<int>> b(n + 2, vector<int>(m + 2, 0));
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= m; j++) {
                b[i][j] = a[j][i];
            };
        };
        return b;
    };

    void Solve() {
        DSU DSU(m * n);

        for (int i = 1; i <= m; i++) {
            for (int j = 1; j <= n; j++) {
                int u = cell(i, j);
                DSU.setColor(u, a[i][j]);

                for (int k = 0; k < 4; k++) {
                    int x = i + dx[k];
                    int y = j + dy[k];
                    if (valid(x, y)) {
                        int v = cell(x, y);
                        if (a[x][y] != a[i][j])
                            DSU.border[u].insert(v);
                        else
                            DSU.unionSet(u, v, a[x][y]);
                    };
                };
            };
        };

        for (const Query &q : queries) {
            int x = q.x, y = q.y, color = q.color;
            int u = cell(x, y);
            if (color == DSU.getColor(u)) continue;

            int root = DSU.findSet(u);
            DSU.setColor(root, color);

            bool merged_in_pass = true;
            while (merged_in_pass) {
                merged_in_pass = false;

                set<int> current_border = DSU.border[root];
                set<int> visited_neighbor_roots;

                for (int v_cell : current_border) {
                    int v_root = DSU.findSet(v_cell);

                    if (v_root == root || visited_neighbor_roots.count(v_root)) {
                        continue;
                    };
                    visited_neighbor_roots.insert(v_root);

                    if (DSU.getColor(v_root) == color) {
                        DSU.unionSet(root, v_root, color);
                        root = DSU.findSet(root);
                        merged_in_pass = true;
                    };
                };
            };
        };

        for (int i = 1; i <= m; i++) {
            for (int j = 1; j <= n; j++) {
                a[i][j] = DSU.getColor(cell(i, j));
            };
        };

        printMatrix(m, n, a);
    };
};  // namespace SUBTASK_3

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    if (fopen("PAINT.INP", "r")) {
        freopen("PAINT.INP", "r", stdin);
        freopen("PAINT.OUT", "w", stdout);
    };

    cin >> m >> n;
    a.resize(m + 2, vector<int>(n + 2, 0));

    for (int i = 1; i <= m; i++) {
        for (int j = 1; j <= n; j++) {
            cin >> a[i][j];
        };
    };

    cin >> q;
    queries.resize(q);
    for (Query &q : queries) cin >> q.x >> q.y >> q.color;

    if (SUBTASK_1::checkSubtask())
        return SUBTASK_1::Solve(), 0;
    if (SUBTASK_2::checkSubtask())
        return SUBTASK_2::Solve(), 0;

    SUBTASK_3::Solve();
};

Compilation message (stderr)

paint.cpp: In function 'int main()':
paint.cpp:257:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  257 |         freopen("PAINT.INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
paint.cpp:258:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  258 |         freopen("PAINT.OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 9 / 9
• Subtask 3: 0 / 31
• Subtask 4: 0 / 52