[틀린문제찾기] 미로찾기

<1차 풀이>

from collections import deque
import math
from sys import stdin

n,m = map(int, input().split())
graph = []
for i in range(n):
    graph.append(list(map(int, input())))
    
#이동할 벡터(상,하,좌,우)
dx = [-1, 1, 0, 0]
dy = [0, 0, -1, 1]

def bfs(x, y):
    q = deque()
    q.append((x, y))
    while q:
        x, y = q.popleft()
        #4방향을 체크
        for i in range(4):
            nx = x + dx[i]
            ny = y + dy[i]
            
            #해당되지 않는 범위 체크
            if 0 <= nx < n and 0 <= ny < m:
                if not graph[nx][ny] == 0:
                    if graph[nx][ny] == 1:
                        graph[nx][ny] = graph[x][y] + 1
                        q.append((nx, ny))
                        
        return graph[n-1][m-1]
    
print(bfs(0,0))

<정답 풀이>

from collections import deque
import math
from sys import stdin

n,m = map(int, input().split())
graph = []
for i in range(n):
    graph.append(list(map(int, input())))
    
#이동할 벡터(상,하,좌,우)
dx = [-1, 1, 0, 0]
dy = [0, 0, -1, 1]

def bfs(x, y):
    q = deque()
    q.append((x, y))
    while q:
        x, y = q.popleft()
        #4방향을 체크
        for i in range(4):
            nx = x + dx[i]
            ny = y + dy[i]
            
            #해당되지 않는 범위 체크
            if nx < 0 or ny < 0 or nx >= n or ny >= m:
                continue
            
            if graph[nx][ny] == 0:
                continue
            
            if graph[nx][ny] == 1:
                graph[nx][ny] = graph[x][y] + 1
                q.append((nx, ny))
                
        
                        
    return graph[n-1][m-1]
    
print(bfs(0,0))

<수정한 풀이>

from collections import deque
import math
from sys import stdin

n,m = map(int, input().split())
graph = []
for i in range(n):
    graph.append(list(map(int, input())))
    
#이동할 벡터(상,하,좌,우)
dx = [-1, 1, 0, 0]
dy = [0, 0, -1, 1]

def bfs(x, y):
    q = deque()
    q.append((x, y))
    while q:
        x, y = q.popleft()
        #4방향을 체크
        for i in range(4):
            nx = x + dx[i]
            ny = y + dy[i]
            
            #해당되지 않는 범위 체크
            if 0 <= nx < n and 0 <= ny < m:
                if not graph[nx][ny] == 0:
                    if graph[nx][ny] == 1:
                        graph[nx][ny] = graph[x][y] + 1
                        q.append((nx, ny))
                        
    return graph[n-1][m-1]
    
print(bfs(0,0))