题解 | BFS
BFS
https://www.nowcoder.com/practice/22da7730da5d4a129a188ba24d22f2bf
from re import S
import sys
s = input()
# pos = s.lower().find('bob')
# pos = s.upper().find('BOB')
# print(pos)
pos = -1
n = len(s)
for i in range(n-2):
if s[i:i+3].lower() == 'bob':
pos = i
break
print(pos)