/
bitOps.go
83 lines (72 loc) · 1.9 KB
/
bitOps.go
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
// MIT License
//
// Copyright (c) 2019 Huang Jian
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
/*
&
|
^
<<
>>
a & b : 按位与
a | b : 按位或
^a : 对 a 进行每一位取反
a ^ b : 按位异或,相同为 0,不同为 1
a&^b : a&^b==a&(^b)
*/
package ubit
// IsPowerOfTwo judege whether x is 2^n
func IsPowerOfTwo(x int) bool {
return x&(x-1) == 0
}
// CountBits count bits of number x
func CountBits(x int) int {
count := 0
for x > 0 {
x = x & (x - 1)
count++
}
return count
}
// Div2 x / 2
func Div2(x int) int {
return x >> 1
}
// IsOdd 判断 x 是不是奇数
func IsOdd(x int) bool {
return x&0x01 == 0x01
}
// IsEven 判断 x 是不是偶数
func IsEven(x int) bool {
return x&0x01 == 0x00
}
// Negative 正数-->负数,负数-->正数
func Negative(x int) int {
return ^x + 1
}
/*
Swap a, b = b, a
*/
func Swap(a, b int) (int, int) {
a ^= b
b ^= a
a ^= b
return a, b
}