[python]伯準16953 A→B(Greedy/BFS)

しゅつりょく

入力例1

2 → 4 → 8 → 81 → 162

サンプル出力1

入力例2

サンプル出力2

入力例3

100 → 200 → 2001 → 4002 → 40021

サンプル出力3

📌 に答える

💬 Greedy Code

import sys
input = sys.stdin.readline

a, b = map(int, input().split())
cnt = 1

while a != b:
    if b % 2 != 0: # 홀수면
        if str(b)[len(str(b))-1] == '1' and b != 1: # 끝자리가 1이면 1 제거
            b = int(str(b)[:len(str(b))-1])
            cnt += 1
        else: # 아니면 -1 출력
            cnt = -1
            break
    elif b % 2 == 0: # 짝수면 나누기 2
        b //= 2
        cnt += 1

print(cnt)

💡 Greedy Solution

💬 BFS Code

import sys
from collections import deque
input = sys.stdin.readline

def bfs():
    q = deque([(a, 1)])
    while q:
        x, dist = q.popleft()
        if x == b:
            print(dist)
            sys.exit(0)
        for nx in [x * 2, int(str(x) + '1')]:
            if nx <= b:
                q.append((nx, dist + 1))
    print(-1)

a, b = map(int, input().split())
bfs()

💡 BFS Solution