๐Ÿ˜Ž ๊ณต๋ถ€ํ•˜๋Š” ์ง•์ง•์•ŒํŒŒ์นด๋Š” ์ฒ˜์Œ์ด์ง€?

[๊ฐ„๋‹จํ•œ BFS] ๋ฏธ๋กœ ๊ฒŒ์ž„ ๋ณธ๋ฌธ

๐Ÿฆฅ ์ฝ”ํ…Œ

[๊ฐ„๋‹จํ•œ BFS] ๋ฏธ๋กœ ๊ฒŒ์ž„

์ง•์ง•์•ŒํŒŒ์นด 2023. 4. 12. 01:26
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์ฐธ๊ณ  ํ–ˆ์Šต๋‹ˆ๋‹ค. ๊ฐ์‚ฌํ•ฉ๋‹ˆ๋‹ค
https://doyyy.tistory.com/144
๋ฏธ๋กœ๊ฒŒ์ž„
๋™๋นˆ์ด๋Š” N X M ํฌ๊ธฐ์˜ ์ง์‚ฌ๊ฐํ˜• ํ˜•ํƒœ์˜ ๋ฏธ๋กœ์— ๊ฐ‡ํ˜”๋‹ค
๋ฏธ๋กœ์—๋Š” ์—ฌ๋Ÿฌ ๋งˆ๋ฆฌ์˜ ๊ดด๋ฌผ์ด ์žˆ์–ด ์ด๋ฅผ ํ”ผํ•ด ํƒˆ์ถœํ•ด์•ผ ํ•œ๋‹ค
๋™๋นˆ์ด์˜ ์œ„์น˜๋Š” (1,1)์ด๋ฉฐ ๋ฏธ๋กœ์˜ ์ถœ๊ตฌ๋Š” (N,M)์˜ ์œ„์น˜์— ์กด์žฌํ•˜๋ฉฐ ํ•œ ๋ฒˆ์— ํ•œ ์นธ์”ฉ ์ด๋™
์ด ๋•Œ ๊ดด๋ฌผ์ด ์žˆ๋Š” ๋ถ€๋ถ„์€ 0์œผ๋กœ, ๊ดด๋ฌผ์ด ์—†๋Š” ๋ถ€๋ถ„์€ 1๋กœ ํ‘œ์‹œ
๋ฏธ๋กœ๋Š” ๋ฐ˜๋“œ์‹œ ํƒˆ์ถœํ•  ์ˆ˜ ์žˆ๋Š” ํ˜•ํƒœ๋กœ ์ œ์‹œ

์ด๋•Œ ๋™๋นˆ์ด๊ฐ€ ํƒˆ์ถœํ•˜๊ธฐ ์œ„ํ•ด ์›€์ง์—ฌ์•ผ ํ•˜๋Š” ์ตœ์†Œ ์นธ์˜ ๊ฐœ์ˆ˜
์นธ์„ ์…€๋•Œ๋Š” ์‹œ์ž‘ ์นธ๊ณผ ๋งˆ์ง€๋ง‰ ์นธ์„ ๋ชจ๋‘ ํฌํ•จํ•ด์„œ ๊ณ„์‚ฐ
from collections import deque
# N X M ๋ฏธ๋กœ
n, m = map(int, input().split())
# ๋ฏธ๋กœ์˜ ์ •๋ณด
graph = []
for i in range(n):
	graph.append(list(map(int, input().split())))

# ๋ฐฉํ–ฅ ๋ฒกํ„ฐ
dx = [-1, 1, 0, 0]
dy = [0, 0, -1, 1]

def bfs(x, y):
	queue = deque()
	queue.append([x, y])
	while queue:
		# ๊ฐ’ ์ดˆ๊ธฐํ™”
		x, y = queue.popleft()
		# 4๊ฐ€์ง€ ๋ฐฉํ–ฅ
		for i in range(4):
			nx = x + dx[i]
			ny = y + dy[i]
			# ๋ฒ”์œ„ ๋ฒ—์–ด๋‚œ ๊ฒฝ์šฐ ๋ฌด์‹œ
			if nx < 0 or ny < 0 or nx >= n or ny >= m:
				continue
			# ๊ดด๋ฌผ ์žˆ๋Š” ๊ฒฝ์šฐ ๋ฌด์‹œ
			if graph[nx][ny] == 0:
				continue
			# ๊ดด๋ฌผ์ด ์—†๋Š” ๋ถ€๋ถ„์ด๋‹ค!
			# ํ˜„์žฌ ์œ„์น˜์—์„œ ์ด๋™!
			if graph[nx][ny] == 1:
				queue.append([nx,ny])
				graph[nx][ny] = graph[x][y] + 1
bfs(0,0)
print(graph[n-1][m-1])
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