1 extern crate petgraph;
2 extern crate rand;
3
4 use petgraph::unionfind::UnionFind;
5 use rand::{thread_rng, ChaChaRng, Rng, SeedableRng};
6 use std::collections::HashSet;
7
8 #[test]
uf_test()9 fn uf_test() {
10 let n = 8;
11 let mut u = UnionFind::new(n);
12 for i in 0..n {
13 assert_eq!(u.find(i), i);
14 assert_eq!(u.find_mut(i), i);
15 assert!(!u.union(i, i));
16 }
17
18 u.union(0, 1);
19 assert_eq!(u.find(0), u.find(1));
20 u.union(1, 3);
21 u.union(1, 4);
22 u.union(4, 7);
23 assert_eq!(u.find(0), u.find(3));
24 assert_eq!(u.find(1), u.find(3));
25 assert!(u.find(0) != u.find(2));
26 assert_eq!(u.find(7), u.find(0));
27 u.union(5, 6);
28 assert_eq!(u.find(6), u.find(5));
29 assert!(u.find(6) != u.find(7));
30
31 // check that there are now 3 disjoint sets
32 let set = (0..n).map(|i| u.find(i)).collect::<HashSet<_>>();
33 assert_eq!(set.len(), 3);
34 }
35
36 #[test]
uf_test_with_equiv()37 fn uf_test_with_equiv() {
38 let n = 8;
39 let mut u = UnionFind::new(n);
40 for i in 0..n {
41 assert_eq!(u.find(i), i);
42 assert_eq!(u.find_mut(i), i);
43 assert!(u.equiv(i, i));
44 }
45
46 u.union(0, 1);
47 assert!(u.equiv(0, 1));
48 u.union(1, 3);
49 u.union(1, 4);
50 u.union(4, 7);
51 assert!(u.equiv(0, 7));
52 assert!(u.equiv(1, 3));
53 assert!(!u.equiv(0, 2));
54 assert!(u.equiv(7, 0));
55 u.union(5, 6);
56 assert!(u.equiv(6, 5));
57 assert!(!u.equiv(6, 7));
58
59 // check that there are now 3 disjoint sets
60 let set = (0..n).map(|i| u.find(i)).collect::<HashSet<_>>();
61 assert_eq!(set.len(), 3);
62 }
63
64 #[test]
uf_rand()65 fn uf_rand() {
66 let n = 1 << 14;
67 let mut rng = ChaChaRng::from_rng(thread_rng()).unwrap();
68 let mut u = UnionFind::new(n);
69 for _ in 0..100 {
70 let a = rng.gen_range(0, n);
71 let b = rng.gen_range(0, n);
72 let ar = u.find(a);
73 let br = u.find(b);
74 assert_eq!(ar != br, u.union(a, b));
75 }
76 }
77
78 #[test]
uf_u8()79 fn uf_u8() {
80 let n = 256;
81 let mut rng = ChaChaRng::from_rng(thread_rng()).unwrap();
82 let mut u = UnionFind::<u8>::new(n);
83 for _ in 0..(n * 8) {
84 let a = rng.gen();
85 let b = rng.gen();
86 let ar = u.find(a);
87 let br = u.find(b);
88 assert_eq!(ar != br, u.union(a, b));
89 }
90 }
91
92 #[test]
labeling()93 fn labeling() {
94 let mut u = UnionFind::<u32>::new(48);
95 for i in 0..24 {
96 u.union(i + 1, i);
97 }
98 for i in 25..47 {
99 u.union(i, i + 1);
100 }
101 u.union(23, 25);
102 u.union(24, 23);
103 let v = u.into_labeling();
104 assert!(v.iter().all(|x| *x == v[0]));
105 }
106