🟩 [백준] [Python] [DFS/BFS] 2667번_단지번호붙이기

문제

https://www.acmicpc.net/problem/2667

2667번: 단지번호붙이기

풀이

DFS를 사용한 풀이

# 백준 2667번 문제 - 단지번호붙이기
n = int(input())
graph = []
num = []

for i in range(n):
    graph.append(list(map(int, input())))

dx = [0,0,1,-1]
dy = [1,-1,0,0]

def DFS(x,y):
    if x < 0 or x >= n or y < 0 or y >= n:
        return False
    
    if graph[x][y] == 1:
        global cnt
        cnt += 1
        graph[x][y] = 0
        for i in range(4):
            nx = x + dx[i]
            ny = y + dy[i]
            DFS(nx, ny)
        return True
    return False

cnt = 0 
result = 0

for i in range(n):
    for j in range(n):
        if DFS(i, j) == True:
            num.append(cnt)
            result += 1
            cnt = 0

num.sort()
print(result)
for i in num:
    print(i)

 

 

BFS를 사용한 풀이

# BFS
from collections import deque

dx = [0, 0, 1, -1]
dy = [1, -1, 0, 0]


def bfs(graph, a, b):
    n = len(graph)
    queue = deque()
    queue.append((a, b))
    graph[a][b] = 0
    count = 1

    while queue:
        x, y = queue.popleft()
        for i in range(4):
            nx = x + dx[i]
            ny = y + dy[i]
            if nx < 0 or nx >= n or ny < 0 or ny >= n:
                continue
            if graph[nx][ny] == 1:
                graph[nx][ny] = 0
                queue.append((nx, ny))
                count += 1
    return count


n = int(input())
graph = []
for i in range(n):
    graph.append(list(map(int, input())))

cnt = []
for i in range(n):
    for j in range(n):
        if graph[i][j] == 1:
            cnt.append(bfs(graph, i, j))

cnt.sort()
print(len(cnt))
for i in range(len(cnt)):
    print(cnt[i])