Submission #576437

#	Time	Username	Problem	Language	Result	Execution time	Memory
576437		timmyfeng	Paint (COI20_paint)	C++17	100 / 100	931 ms	492444 KiB

paint

#include <bits/stdc++.h>
using namespace std;

#define V vector
 
const int D[] = {0, 1, 0, -1}, M = 512, C = 1e5;
 
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
 
	int n, m; cin >> n >> m;
 
	V<int> co(n * m);
	for (auto &i : co) cin >> i;
 
    V<V<int>> ne(n * m), me(n * m);
	V<int> le(n * m);
 
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < m; ++j) {
			int id = i * m + j;
			le[id] = id;
			me[id].push_back(id);
			for (int d = 0; d < 4; ++d) {
				int in = i + D[d], jn = j + D[(d + 1) % 4];
				if (0 <= in && in < n && 0 <= jn && jn < m) {
                    ne[id].push_back(in * m + jn);
				}
			}
		}
	}
 
	V<V<set<int>>> nc(n * m);
    V<bool> iv(n * m);
    set<int> bg;
 
    auto normalize = [&](int a) {
        V<int> nn;
        for (auto b : ne[a]) {
            b = le[b];
            if (le[b] != a && !iv[b]) {
                nn.push_back(b);
                iv[b] = true;
            }
        }
        swap(ne[a], nn);
    };
 
	auto update = [&](int a) {
        if ((int) me[a].size() >= M) {
            for (auto b : bg) {
                if (a != b && nc[a][co[b]].count(b))
                    nc[b][co[a]].insert(a);
            }
        } else {
            normalize(a);
            for (auto b : bg) {
                if (iv[b])
                    nc[b][co[a]].insert(a);
            }
            for (auto b : ne[a]) iv[b] = false;
        }
	};
 
	auto merge = [&](int a, int b) {
		if (me[a].size() < me[b].size()) swap(a, b);
 
        if ((int) me[a].size() < M && (int) (me[a].size() + me[b].size()) >= M) {
            nc[a].resize(C);
            for (auto u : ne[a])
                nc[a][co[le[u]]].insert(le[u]);
            bg.insert(a);
        }
 
        if ((int) (me[a].size() + me[b].size()) >= M) {
            for (auto u : ne[b])
                nc[a][co[le[u]]].insert(le[u]);
            nc[b].clear();
            bg.erase(b);
        }
 
		for (auto i : me[b]) le[i] = a;
 
		me[a].insert(me[a].end(), me[b].begin(), me[b].end());
		me[b].clear();
 
		ne[a].insert(ne[a].end(), ne[b].begin(), ne[b].end());
		ne[b].clear();
	};
 
	auto fill = [&](int a, int c) {
		a = le[a];
 
        while (true) {
            if ((int) me[a].size() < M) {
                bool merged = false;
                auto in = ne[a];
                for (auto b : in) {
                    b = le[b];
                    if (b != a && co[b] == c) {
                        merged = true;
                        merge(a, b);
                        a = le[a];
                    }
                }
                if (!merged) break;
            } else {
                if (nc[a][c].empty()) break;
 
                int b = *nc[a][c].begin();
                nc[a][c].erase(b);
                b = le[b];
 
                if (b != a && co[b] == c) {
                    merge(a, b);
                    a = le[a];
                }
            }
        }
 
		co[a] = c;
		update(a);
	};
 
	for (int i = 0; i < n * m; ++i)
		fill(i, co[i]);
 
	int q; cin >> q;
 
	while (q--) {
		int i, j, c; cin >> i >> j >> c; --i, --j;
		fill(i * m + j, c);
	}
 
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < m; ++j) {
			cout << co[le[i * m + j]] << " ";
		}
		cout << "\n";
	}
}

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