[백준] 2583 영역 구하기

[백준] 2583 영역 구하기

• https://www.acmicpc.net/problem/2583

#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;

int N,M;
int board[101][101] = { 0 };
int visited[101][101] = { 0 };

bool inRange(int r, int c) {
	if (r < 0 || r >= N) return false;
	if (c < 0 || c >= M) return false;
	return true;
}

int dirR[4] = { 0, 0, 1, -1 };
int dirC[4] = { 1, -1, 0, 0 };

//bfs하며 방문한 영역의 크기 반환
int bfs(int startR, int startC) {
	queue<pair<int, int>> q;
	q.push({ startR, startC });

	int size = 0;
	while (!q.empty()) {
		int curR = q.front().first; 
		int curC = q.front().second;
		q.pop();

		if (visited[curR][curC]) continue;
		visited[curR][curC] = 1;
		size++;

		//상하좌우 인접한 칸 bfs
		for (int d = 0; d < 4; ++d) {
			int nextR = curR + dirR[d];
			int nextC = curC + dirC[d];

			if (!inRange(nextR, nextC)) continue;
			if (visited[nextR][nextC]) continue;
			if (board[nextR][nextC] == 1) continue;

			q.push({ nextR, nextC });
		}
	}

	return size;
}


int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL); cout.tie(NULL);
	
	int K;
	cin >> M >> N >> K;

	for (int i = 0; i < K; ++i) {
		int x1, y1, x2, y2;
		cin >> x1 >> y1 >> x2 >> y2;

		for (int r = x1; r < x2; ++r) {
			for (int c = y1; c < y2; ++c) {
				board[r][c] = 1;
			}
		}
	}

	int cnt = 0;
	vector<int> sizes;

	for (int i = 0; i < N; ++i) {
		for (int j = 0; j < M; ++j) {
			if ((board[i][j] == 0) && (!visited[i][j])) {
				sizes.push_back(bfs(i, j));
				cnt++;
			}
		}
	}

	cout << cnt <<"\n";
	//오름차순 정렬
	sort(sizes.begin(), sizes.end());
	for (int i = 0; i < sizes.size(); ++i) {
		cout << sizes[i] << " ";
	}
	return 0;
}