OJ刷题记录：L1-608-岛屿数量(20分)

#include <iostream>
#include <vector>
#include <queue>

using namespace std;

void changeIsland(vector<vector<int>> &matrix, int originX, int originY) {
	const int bx[] = {0, 0, -1, 1};
	const int by[] = {1, -1, 0, 0};

	matrix[originX][originY] = 0;
	
	queue<pair<int, int>> q;
	q.emplace(pair<int, int>(originX, originY));
	
	int x, y;
	for (; !q.empty();) {
		x = q.front().first;
		y = q.front().second;
		q.pop();
		
		for (int i = 0; i < 4; i++) {
			if (x + bx[i] >= 0 && x + bx[i] < matrix.size() && y + by[i] >= 0 && y + by[i] < matrix[0].size()) {
				if (matrix[x + bx[i]][y + by[i]] == 1) {
					matrix[x + bx[i]][y + by[i]] = 0;
					q.emplace(pair<int, int>(x + bx[i], y + by[i]));
				}
			}
		}
	}	
}

int main() {
	int row, column, sum = 0;
	
	cin >> row >> column;

	vector<int> arr(column);
	vector<vector<int>> matrix;
	
	for (int i = 0; i < row; i++) {
		for (int j = 0; j < column; j++) {
			cin >> arr[j];
		}
		matrix.emplace_back(arr);
	}
	
	for (int i = 0; i < row; i++) {
		for (int j = 0; j < column; j++) {
			if (matrix[i][j] == 1) {
				sum++;
				changeIsland(matrix, i, j);
			}
		}
	}
	
	cout << sum;
	
	return 0;
}