1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
|
"""
https://leetcode.com/problems/string-to-integer-atoi/description/
"""
class (object):
def myAtoi(self, st):
"""
:type str: str
:rtype: int
>>> s = Solution()
>>> s.myAtoi("42")
42
>>> s.myAtoi(" -42")
-42
>>> s.myAtoi("4193 with words")
4193
>>> s.myAtoi("words and 987")
0
>>> s.myAtoi("-91283472332")
-2147483648
>>> s.myAtoi(" -12-45")
-12
>>> s.myAtoi("-")
0
>>> s.myAtoi("- 1")
0
>>> s.myAtoi("- 1")
0
>>> s.myAtoi("- -1")
0
>>> s.myAtoi("+1")
1
>>> s.myAtoi("123 456")
123
"""
INT_MAX = 2**31 - 1
INT_MIN = -2**31
start, end = -1, -1
if st == "":
return 0
for idx, i in enumerate(st):
if i == " ":
if start != -1:
end = idx
break
elif i in set({"-", "+"}):
if start == -1:
start = idx
else:
end = idx
break
elif i in set({"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"}):
if start == -1:
start = idx
else:
if start == -1:
return 0
else:
end = idx
break
try:
if end == -1:
value = int(st[start:])
else:
value = int(st[start:end])
except ValueError:
return 0
if value > INT_MAX:
return INT_MAX
if value < INT_MIN:
return INT_MIN
return value
def myAtoi2(self, st):
"""
:type str: str
:rtype: int
"""
import re
st = st.strip()
try:
res = re.search('(^[+-]?d+)', st).group()
res = int(res)
res = res if res <= 2147483647 else 2147483647
res = res if res >= -2147483648 else -2147483648
except:
res = 0
return res
|
近期评论