[백준/파이썬] 1743번

📍백준 1743 문제

https://www.acmicpc.net/problem/1743

코드

from collections import deque
import sys
input = sys.stdin.readline
dx = [0, 0, -1, 1]
dy = [-1, 1, 0, 0]


def bfs(x, y):
    que = deque()
    road[x][y] = 1
    que.append((x, y))
    cnt = 1
    visited[x][y] = True
    while que:
        x, y = que.popleft()
        for i in range(4):
            nx = x + dx[i]
            ny = y + dy[i]
            if 0 <= nx < n and 0 <= ny < m and road[nx][ny] == -1 and visited[nx][ny] == False:
                cnt += 1
                road[nx][ny] = 1
                visited[nx][ny] = True
                que.append((nx, ny))
    return cnt


n, m, k = map(int, input().split())
road = [[0 for _ in range(m)]for _ in range(n)]
visited = [[False for i in range(m)]for _ in range(n)]


for _ in range(k):
    x, y = map(int, input().split())
    x -= 1
    y -= 1
    road[x][y] = -1
res = 0
for i in range(n):
    for j in range(m):
        if road[i][j] == -1 and visited[i][j] == False:
            res = max(res, bfs(i, j))


print(res)

풀이

• 이중반복문을 통해 road[i][j] == -1이고 visited[i][j] == False이라면 bfs을 실행합니다.
• 최대 크기를 구해야 하므로 max(현재 max값, bfs에서 나온 값)을 통해 최대 크기를 구합니다.