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
//! Check whether an arc exists in a digraph.
//!
//! To check whether an edge exists between `u` to `v`, see [`HasEdge`].
//!
//! # Examples
//!
//! ```
//! use graaf::{
//! AddArc,
//! AdjacencyList,
//! Empty,
//! HasArc,
//! };
//!
//! let mut digraph = AdjacencyList::empty(3);
//!
//! digraph.add_arc(0, 1);
//! digraph.add_arc(0, 2);
//! digraph.add_arc(1, 0);
//!
//! assert!(digraph.has_arc(0, 1));
//! assert!(digraph.has_arc(0, 2));
//! assert!(digraph.has_arc(1, 0));
//! assert!(!digraph.has_arc(1, 2));
//! assert!(!digraph.has_arc(2, 0));
//! assert!(!digraph.has_arc(2, 1));
//! ```
//!
//! [`HasEdge`]: crate::HasEdge
/// Check whether an arc exists in a digraph.
pub trait HasArc {
/// Check whether an arc exists in the digraph.
///
/// # Arguments
///
/// * `u`: The tail vertex.
/// * `v`: The head vertex.
///
/// # Panics
///
/// `has_arc` may not panic if `u` and `v` aren't in the digraph.
///
/// # Examples
///
/// ```
/// use graaf::{
/// AddArc,
/// AdjacencyList,
/// Empty,
/// HasArc,
/// };
///
/// let mut digraph = AdjacencyList::empty(3);
///
/// digraph.add_arc(0, 1);
/// digraph.add_arc(0, 2);
/// digraph.add_arc(1, 0);
///
/// assert!(digraph.has_arc(0, 1));
/// assert!(digraph.has_arc(0, 2));
/// assert!(digraph.has_arc(1, 0));
/// assert!(!digraph.has_arc(1, 2));
/// assert!(!digraph.has_arc(2, 0));
/// assert!(!digraph.has_arc(2, 1));
/// ```
#[must_use]
fn has_arc(&self, u: usize, v: usize) -> bool;
}
/// `HasArc` proptests
#[macro_export]
macro_rules! proptest_has_arc {
($type:ty) => {
use {
proptest::proptest,
$crate::Empty,
};
proptest! {
#[test]
fn has_arc_out_of_bounds(order in 1..25_usize) {
let digraph = <$type>::empty(order);
for u in 0..order {
assert!(!digraph.has_arc(u, order));
assert!(!digraph.has_arc(order, u));
}
}
}
};
}