1697번: 숨바꼭질 (그래프, BFS) - Fastcampus

www.acmicpc.net/problem/1697

1697번: 숨바꼭질

from collections import deque


def bfs(start, K):
    qu = deque([(start, 0)])
    visited = [0] * 100001

    while qu:
        x, sec = qu.popleft()
        if not visited[x]:
            visited[x] = 1
            if x == K:
                return sec

            for e in (x-1, x+1, 2*x):
                if 0 <= e <= 100000:
                    qu.append((e, sec+1))


N, K = map(int, input().split())
print(bfs(N, K))