Submission #207853

#	Time	Username	Problem	Language	Result	Execution time	Memory
207853		opukittpceno_hhr	Dango Maker (JOI18_dango_maker)	C++17	0 / 100	176 ms	262148 KiB

dango_maker

#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <string>
#include <cmath>
#include <cstdio>
#include <iomanip>
#include <fstream>
#include <cassert>
#include <cstring>
#include <unordered_set>
#include <unordered_map>
#include <numeric>
#include <ctime>
#include <bitset>
#include <complex>
#include <random>

using namespace std;

const int N = 3001;

int a[N][N];

int read() {
	char c;
	cin >> c;
	if (c == 'R') return 0;
	if (c == 'G') return 1;
	if (c == 'W') return 2;
	assert(false);
	return -1;
}

int n, m;

int ok(int i, int j, int dir) {
	if (dir == 0) {
		if (i == 0 || i + 1 == n) return 0;
		return a[i - 1][j] == 0 && a[i][j] == 1 && a[i + 1][j] == 2;
	} else {
		if (j == 0 || j + 1 == m) return 0;
		return a[i][j - 1] == 0 && a[i][j] == 1 && a[i][j + 1] == 2;
	}
}

vector<pair<int, int>> gt(int i, int j, int dir) {
	if (dir == 0) {
		return {{i - 1, j}, {i, j}, {i + 1, j}};
	} else {
		return {{i, j - 1}, {i, j}, {i, j + 1}};
	}
}

bool inter(vector<pair<int, int>> &x, vector<pair<int, int>> &y) {
	for (auto f : x) {
		for (auto s : y) {
			if (f == s) return 1;
		}
	}
	return 0;
}

vector<vector<int>> g;

vector<int> used;
vector<int> clr;

void dfs(int v, int c) {
	clr[v] = c;
	used[v] = 1;
	for (auto t : g[v]) {
		if (!used[t]) dfs(t, c ^ 1);
	}
}

pair<int, int> parse(int v) {
	v %= n * m;
	return {v / m, v % m};
}

vector<int> mt;
vector<vector<int>> ng;

int sm(int v) {
	if (used[v]) return 0;
	for (auto t : ng[v]) {
		if (mt[t] == -1 || sm(mt[t])) {
			mt[t] = v;
			return 1;
		}
	}
	return 0;
}

int solve_mathing() {
	int f = (int)g.size();
	vector<int> lp, rp;
	for (int i = 0; i < f; i++) {
		if (!clr[i]) lp.push_back(i);
		else rp.push_back(i); 
	}
	mt.resize(rp.size(), -1);
	ng.resize(lp.size());
	for (int i = 0; i < f; i++) {
		for (auto j : g[i]) {
			if (!clr[i]) {
				int x = lower_bound(lp.begin(), lp.end(), i) - lp.begin();
				int y = lower_bound(rp.begin(), rp.end(), j) - rp.begin();
				ng[x].push_back(y);
			}
		}
	}
	used.clear();
	used.resize(rp.size());
	for (int i = 0; i < (int)lp.size(); i++) {
		fill(used.begin(), used.end(), 0);
		sm(i);
	}
	int ans = 0;
	for (auto t : mt) ans += (t != -1);
	return ans;
}

int solve() {
	vector<int> tk;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			if (ok(i, j, 0)) tk.push_back({i * m + j});
			if (ok(i, j, 1)) tk.push_back({i * m + j + n * m});
		}
	}
	auto get  = [&](int x) {
		int v = tk[x];
		int tp = (v / (n * m));
		v %= n * m;
		int i = v / m;
		int j = v % m;
		return gt(i, j, tp);
	};
	g.clear();
	used.clear();
	clr.clear();
	g.resize(tk.size());
	used.resize(tk.size());
	clr.resize(tk.size());
	for (int i = 0; i < (int)tk.size(); i++) {
		for (int j = i + 1; j < (int)tk.size(); j++) {
			vector<pair<int, int>> f = get(i);
			vector<pair<int, int>> s = get(j);
			if (inter(f, s)) {
				g[i].push_back(j);
				g[j].push_back(i);
				auto x = parse(tk[i]);
				auto y = parse(tk[j]);
				int lol = abs(x.first - y.first) + abs(x.second - y.second); 
				assert(lol == 0 || lol == 2);
			}
		}
	}
	int f = (int)(tk.size());
	{
		for (int i = 0; i < f; i++) {
			if (!used[i]) dfs(i, 0);
		}
		for (int i = 0; i < f; i++) {
			for (auto j : g[i]) {
				assert(clr[i] != clr[j]);
			}
		}
	}
	return solve_mathing();
}
signed main() {
	ios_base::sync_with_stdio(false);
	cin.tie(0);

	cin >> n >> m;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			a[i][j] = read();
		}
	}
	cout << solve() << endl;

	// while (true) {
	// 	for (int i = 0; i < n; i++) {
	// 		for (int j = 0; j < m; j++) {
	// 			a[i][j] = rand() % 3;
	// 		}
	// 	}
	// 	string lol = "RGW";
	// 	cout << "TEST" << endl;
	// 	cout << n << ' ' << m << endl;
	// 	for (int i = 0; i < n; i++) {
	// 		for (int j = 0; j < m; j++) {
	// 			cout << lol[a[i][j]];
	// 		}
	// 		cout << endl;
	// 	}
	// 	cout << solve() << endl;
	// }
}

• Subtask 1: 0 / 13
• Subtask 2: 0 / 20
• Subtask 3: 0 / 67