백준 4963번 섬의 개수 C++

출처 : https://www.acmicpc.net/problem/4963

 

bfs를 이용해서 해결하였다.

 

#include <iostream>
#include <string>
#include <vector>
#include <math.h>
#include <algorithm>
#include <utility>
#include <stack>
#include <queue>
#include <math.h>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <iomanip>

using namespace std;
using ll = long long;

int dRow[8] = { -1,-1, 0, 1, 1, 1, 0,-1 };
int dCol[8] = {  0, 1, 1, 1, 0,-1,-1,-1 };

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	while (true) {
		int w, h;
		cin >> w >> h;
		if (w == 0 && h == 0) break;
		vector<vector<int>> board(h, vector<int>(w));
		vector<vector<bool>> found(h, vector<bool>(w, false));
		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++) {
				cin >> board[i][j];
			}
		}
		int cnt = 0;
		queue<pair<int, int>> q;
		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++) {
				if (board[i][j] == 0) continue;
				if (found[i][j]) continue;
				q.push({ i,j });
				found[i][j] = true;
				cnt++;
				while (!q.empty()) {
					auto curr = q.front();
					q.pop();
					for (int k = 0; k < 8; k++) {
						int nextRow = curr.first + dRow[k];
						int nextCol = curr.second + dCol[k];
						if (nextRow < 0 || nextRow >= h) continue;
						if (nextCol < 0 || nextCol >= w) continue;
						if (board[nextRow][nextCol] == 0) continue;
						if (found[nextRow][nextCol]) continue;
						q.push({ nextRow,nextCol });
						found[nextRow][nextCol] = true;
					}
				}
			}
		}
		cout << cnt << "\n";
	}
};