/usr/include/sdsl/inv_perm_support.hpp is in libsdsl-dev 2.0.3-4.
This file is owned by root:root, with mode 0o644.
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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 | /* sdsl - succinct data structures library
Copyright (C) 2014 Simon Gog
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see http://www.gnu.org/licenses/ .
*/
/*! \file inv_perm_support.hpp
\brief inv_perm_support.hpp contains a class which adds access to the
inverse of a permutation.
\author Simon Gog
*/
#ifndef INCLUDED_SDSL_INV_PERM_SUPPORT
#define INCLUDED_SDSL_INV_PERM_SUPPORT
#include "int_vector.hpp"
#include "iterators.hpp"
#include "bit_vectors.hpp"
#include "rank_support.hpp"
namespace sdsl
{
//! Class inv_perm_support adds access to the inverse of a permutation.
/*!
* \tparam t_s Sampling parameter of the inverse permutation.
* \tparam t_bv Type of the bitvector used to indicate back-pointers.
* \tparam t_rank Type of rank_support to rank the indicator bitvector.
*
* This support class adds access to the inverse of a permutation in at
* most \(t_s\) steps. It takes about \(1/t_s \log n\) space, where \(n\)
* is the size of the supported permutation.
*
* \par References
* [1] J. Munro, R. Raman, V. Raman, S. Rao: ,,Succinct representation
* of permutations'', Proceedings of ICALP 2003
*/
template<uint64_t t_s=32, class t_bv=bit_vector, class t_rank=typename bit_vector::rank_1_type>
class inv_perm_support
{
public:
typedef int_vector<> iv_type;
typedef iv_type::size_type size_type;
typedef iv_type::value_type value_type;
typedef iv_type::difference_type difference_type;
typedef random_access_const_iterator<inv_perm_support> const_iterator;
typedef t_bv bit_vector_type;
typedef t_rank rank_type;
private:
const iv_type* m_v = nullptr; // pointer to supported permutation
iv_type m_back_pointer; // back pointers
bit_vector_type m_marked; // back pointer marking
rank_type m_rank_marked; // rank support for back pointer marking
public:
inv_perm_support() {};
inv_perm_support(const inv_perm_support& p) : m_v(p.m_v),
m_back_pointer(p.m_back_pointer), m_marked(p.m_marked),
m_rank_marked(p.m_rank_marked) {
m_rank_marked.set_vector(&m_marked);
}
inv_perm_support(inv_perm_support&& p) {
*this = std::move(p);
}
//! Constructor
inv_perm_support(const iv_type* v) : m_v(v) {
bit_vector marked = bit_vector(m_v->size(), 0);
bit_vector done = bit_vector(m_v->size(), 0);
size_type max_back_pointer = 0;
for (size_type i = 0; i < m_v->size(); ++i) {
if (!done[i]) {
done[i] = 1;
size_type back_pointer=i, j = i, j_new=0;
uint64_t steps = 0, all_steps = 0;
while ((j_new=(*m_v)[j]) != i) {
j = j_new;
done[j] = 1;
++steps; ++all_steps;
if (t_s == steps) {
max_back_pointer = std::max(max_back_pointer, back_pointer);
marked[j] = 1;
steps = 0;
back_pointer = j;
}
}
if (all_steps > t_s) {
marked[i] = 1;
max_back_pointer = std::max(max_back_pointer, back_pointer);
}
}
}
m_marked = t_bv(std::move(marked));
util::init_support(m_rank_marked, &m_marked);
done = bit_vector(m_v->size(), 0);
size_type n_bp = m_rank_marked(m_v->size());
m_back_pointer = int_vector<>(n_bp, 0, bits::hi(max_back_pointer)+1);
for (size_type i = 0; i < m_v->size(); ++i) {
if (!done[i]) {
done[i] = 1;
size_type back_pointer = i, j = i, j_new=0;
uint64_t steps = 0, all_steps = 0;
while ((j_new=(*m_v)[j]) != i) {
j = j_new;
done[j] = 1;
++steps; ++all_steps;
if (t_s == steps) {
m_back_pointer[m_rank_marked(j)] = back_pointer;
steps = 0;
back_pointer = j;
}
}
if (all_steps > t_s) {
m_back_pointer[m_rank_marked(i)] = back_pointer;
}
}
}
}
//! Access operator
value_type operator[](size_type i) const {
size_type j = i, j_new=0;
while ((j_new=(*m_v)[j]) != i) {
if (m_marked[j]) {
j = m_back_pointer[m_rank_marked(j)];
while ((j_new=(*m_v)[j]) != i) j = j_new;
} else {
j = j_new;
}
}
return j;
}
size_type size() const {
return nullptr == m_v ? 0 : m_v->size();
}
//! Returns a const_iterator to the first element.
const_iterator begin()const {
return const_iterator(this, 0);
}
//! Returns a const_iterator to the element after the last element.
const_iterator end()const {
return const_iterator(this, size());
}
void set_vector(const iv_type* v) { m_v = v; }
//! Assignment operation
inv_perm_support& operator=(const inv_perm_support& p) {
if (this != &p) {
m_v = p.m_v;
m_back_pointer = p.m_back_pointer;
m_marked = p.m_marked;
m_rank_marked = p.m_rank_marked;
m_rank_marked.set_vector(&m_marked);
}
return *this;
}
//! Assignment move operation
inv_perm_support& operator=(inv_perm_support&& p) {
if (this != &p) {
m_v = std::move(p.m_v);
m_back_pointer = std::move(p.m_back_pointer);
m_marked = std::move(p.m_marked);
m_rank_marked = std::move(p.m_rank_marked);
m_rank_marked.set_vector(&m_marked);
}
return *this;
}
//! Swap operation
void swap(inv_perm_support& p) {
if (this != &p) {
m_back_pointer.swap(p.m_back_pointer);
m_marked.swap(p.m_marked);
util::swap_support(m_rank_marked, p.m_rank_marked, &m_marked, &(p.m_marked));
}
}
//! Serialize into stream
size_type serialize(std::ostream& out, structure_tree_node* v=nullptr, std::string name="")const {
structure_tree_node* child = structure_tree::add_child(v, name, util::class_name(*this));
size_type written_bytes = 0;
written_bytes += m_back_pointer.serialize(out, child, "back_pointer");
written_bytes += m_marked.serialize(out, child, "marked");
written_bytes += m_rank_marked.serialize(out, child, "rank_marked");
structure_tree::add_size(child, written_bytes);
return written_bytes;
}
//! Load sampling from disk
void load(std::istream& in) {
m_back_pointer.load(in);
m_marked.load(in);
m_rank_marked.load(in, &m_marked);
}
};
} // end namespace sdsl
#endif
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