-
Notifications
You must be signed in to change notification settings - Fork 34
/
_65.java
executable file
·68 lines (65 loc) · 1.9 KB
/
_65.java
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
package com.hit.basmath.learn.others;
/**
* 65. Valid Number
* <p>
* Validate if a given string can be interpreted as a decimal number.
* <p>
* Some examples:
* <p>
* "0" => true
* " 0.1 " => true
* "abc" => false
* "1 a" => false
* "2e10" => true
* " -90e3 " => true
* " 1e" => false
* "e3" => false
* " 6e-1" => true
* " 99e2.5 " => false
* "53.5e93" => true
* " --6 " => false
* "-+3" => false
* "95a54e53" => false
* <p>
* Note: It is intended for the problem statement to be ambiguous. You should gather all requirements up front before implementing one. However, here is a list of characters that can be in a valid decimal number:
* <p>
* 1. Numbers 0-9
* 2. Exponent - "e"
* 3. Positive/negative sign - "+"/"-"
* 4. Decimal point - "."
* <p>
* Of course, the context of these characters also matters in the input.
*/
public class _65 {
public boolean isNumber(String s) {
s = s.trim();
boolean pointSeen = false;
boolean eSeen = false;
boolean numberSeen = false;
boolean numberAfterE = true;
for (int i = 0; i < s.length(); i++) {
if ('0' <= s.charAt(i) && s.charAt(i) <= '9') {
numberSeen = true;
numberAfterE = true;
} else if (s.charAt(i) == '.') {
if (eSeen || pointSeen) {
return false;
}
pointSeen = true;
} else if (s.charAt(i) == 'e') {
if (eSeen || !numberSeen) {
return false;
}
numberAfterE = false;
eSeen = true;
} else if (s.charAt(i) == '-' || s.charAt(i) == '+') {
if (i != 0 && s.charAt(i - 1) != 'e') {
return false;
}
} else {
return false;
}
}
return numberSeen && numberAfterE;
}
}