dsalgo 0.2.6

A package for Datastructures and Algorithms.
Documentation 
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
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172

pub fn path_based(g: &Vec<Vec<usize>>) -> Vec<usize> {
    fn dfs(
        g: &Vec<Vec<usize>>,
        order: &mut Vec<usize>,
        label: &mut Vec<usize>,
        st_0: &mut Vec<usize>,
        st_1: &mut Vec<usize>,
        u: usize,
        ord: &mut usize,
        l: &mut usize,
    ) {
        order[u] = *ord;
        *ord += 1;
        st_0.push(u);
        st_1.push(u);
        for v in g[u].iter().map(|x| *x) {
            if order[v] == g.len() {
                dfs(g, order, label, st_0, st_1, v, ord, l);
            } else if label[v] == g.len() {
                while order[*st_0.last().unwrap()] > order[v] {
                    st_0.pop();
                }
            }
        }
        if *st_0.last().unwrap() == u {
            loop {
                let v = st_1.pop().unwrap();
                label[v] = *l;
                if v == u {
                    break;
                }
            }
            *l += 1;
            st_0.pop();
        }
    }
    let n = g.len();
    let mut order = vec![n; n];
    let mut label = vec![n; n];
    let mut st_0 = Vec::with_capacity(n);
    let mut st_1 = Vec::with_capacity(n);
    let mut ord = 0;
    let mut l = 0;
    for i in 0..n {
        if order[i] == n {
            dfs(
                g, &mut order, &mut label, &mut st_0, &mut st_1, i, &mut ord,
                &mut l,
            );
        }
    }
    label
}

pub fn tarjan_offline(g: &Vec<Vec<usize>>) -> Vec<usize> {
    fn dfs(
        g: &Vec<Vec<usize>>,
        order: &mut Vec<usize>,
        low: &mut Vec<usize>,
        label: &mut Vec<usize>,
        on_stack: &mut Vec<bool>,
        st: &mut Vec<usize>,
        u: usize,
        ord: &mut usize,
        l: &mut usize,
    ) {
        order[u] = *ord;
        low[u] = *ord;
        *ord += 1;
        st.push(u);
        on_stack[u] = true;
        for v in g[u].iter().map(|x| *x) {
            if order[v] == g.len() {
                dfs(g, order, low, label, on_stack, st, v, ord, l);
                if low[v] < low[u] {
                    low[u] = low[v];
                }
            } else if on_stack[v] && order[v] < low[u] {
                low[u] = order[v];
            }
        }
        if low[u] == order[u] {
            loop {
                let v = st.pop().unwrap();
                on_stack[v] = false;
                label[v] = *l;
                if v == u {
                    break;
                }
            }
            *l += 1;
        }
    }
    let n = g.len();
    let mut order = vec![n; n];
    let mut low = vec![n; n];
    let mut label = vec![n; n];
    let mut on_stack = vec![false; n];
    let mut st = Vec::with_capacity(n);
    let mut ord = 0;
    let mut l = 0;
    for i in 0..n {
        if order[i] == n {
            dfs(
                g,
                &mut order,
                &mut low,
                &mut label,
                &mut on_stack,
                &mut st,
                i,
                &mut ord,
                &mut l,
            );
        }
    }
    label
}

pub fn kosaraju(g: &Vec<Vec<usize>>) -> Vec<usize> {
    fn dfs(
        g: &Vec<Vec<usize>>,
        visited: &mut Vec<bool>,
        que: &mut Vec<usize>,
        u: usize,
    ) {
        visited[u] = true;
        for v in g[u].iter() {
            if !visited[*v] {
                dfs(g, visited, que, *v);
            }
        }
        que.push(u);
    }
    fn rev_dfs(
        g: &Vec<Vec<usize>>,
        label: &mut Vec<usize>,
        l: usize,
        u: usize,
    ) {
        label[u] = l;
        for v in g[u].iter() {
            if label[*v] == g.len() {
                rev_dfs(g, label, l, *v);
            }
        }
    }
    let n = g.len();
    let mut visited = vec![false; n];
    let mut que = Vec::with_capacity(n);
    let mut label = vec![n; n];
    let mut l = 0usize;
    for i in 0..n {
        if !visited[i] {
            dfs(g, &mut visited, &mut que, i);
        }
    }
    let mut t = vec![vec![]; n];
    for u in 0..n {
        for v in g[u].iter() {
            t[*v].push(u);
        }
    }
    for i in que.iter().rev() {
        if label[*i] != n {
            continue;
        }
        rev_dfs(&t, &mut label, l, *i);
        l += 1;
    }
    label
}