[프로그래머스] 안전지대

😎코딩테스트 연습>코딩테스트 입문>안전지대

📘 문제풀이

from collections import deque
def solution(board):
    answer = 0
    n = len(board)
    q = deque()
    
    dx = [-1, 1, 0, 0, 1, -1, 1, -1]
    dy = [1, -1, 1, -1, 0, 0, 1, -1]
    
    for i in range(n):
        for j in range(n):
            if board[i][j] == 1:
                q.append((i, j))
    
    while q:
        px, py = q.popleft()
        
        for i in range(8):
            nx = px + dx[i]
            ny = py + dy[i]
            
            if nx < 0 or nx >= n or ny < 0  or ny >= n:
                continue
            if board[nx][ny] == 0:
                board[nx][ny] = 2

    for b in board:
        answer += b.count(0)
    return answer