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
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
pub type Tuple = Vec<i64>;
pub fn create_ducci_sequence(entry_sequence: Tuple) -> Vec<Tuple> {
if !entry_sequence.len().is_power_of_two() {
return Vec::new();
}
let mut res_vector = Vec::new();
let mut current = entry_sequence.clone();
loop {
res_vector.push(current.clone());
if current == vec![0; current.len()] {
break;
}
current = create_following_ducci(current);
}
res_vector
}
pub fn create_following_ducci(tuple: Tuple) -> Tuple {
let mut result = Vec::new();
let mut index = 0;
while index < tuple.len() {
let (a, b) = if index == (tuple.len() - 1) {
(tuple[index], tuple[0])
} else {
(tuple[index], tuple[index + 1])
};
result.push(sub_abs(a, b));
index += 1;
}
result
}
fn sub_abs(a: i64, b: i64) -> i64 {
(a - b).abs()
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_create_ducci_sequence() {
let res = create_ducci_sequence(vec![1, 2, 3, 4]);
assert_eq!(res.len(), 6);
let res = create_ducci_sequence(vec![1, 2, 3, 4, 5]);
assert_eq!(res.len(), 0);
}
#[test]
fn test_create_following_ducci() {
let start = vec![1, 2, 3, 4];
let mut next = create_following_ducci(start);
assert_eq!(next, vec![1, 1, 1, 3]);
next = create_following_ducci(next);
assert_eq!(next, vec![0, 0, 2, 2]);
next = create_following_ducci(next);
assert_eq!(next, vec![0, 2, 0, 2]);
next = create_following_ducci(next);
assert_eq!(next, vec![2, 2, 2, 2]);
next = create_following_ducci(next);
assert_eq!(next, vec![0, 0, 0, 0]);
}
#[test]
fn test_sub_abs() {
let (a, b) = (23, 67);
let res = sub_abs(a, b);
assert_eq!(res, 44);
}
}