lemon/bits/solver_bits.h
author Peter Kovacs <kpeter@inf.elte.hu>
Wed, 25 Mar 2009 15:58:44 +0100
changeset 605 5232721b3f14
parent 459 ed54c0d13df0
child 877 141f9c0db4a3
child 988 8d281761dea4
permissions -rw-r--r--
Rework the interface of NetworkSimplex (#234)

The parameters of the problem can be set with separate functions
instead of different constructors.
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/* -*- mode: C++; indent-tabs-mode: nil; -*-
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 *
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 * This file is a part of LEMON, a generic C++ optimization library.
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 *
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 * Copyright (C) 2003-2008
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 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
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 * (Egervary Research Group on Combinatorial Optimization, EGRES).
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 *
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 * Permission to use, modify and distribute this software is granted
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 * provided that this copyright notice appears in all copies. For
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 * precise terms see the accompanying LICENSE file.
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 *
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 * This software is provided "AS IS" with no warranty of any kind,
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 * express or implied, and with no claim as to its suitability for any
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 * purpose.
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 *
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 */
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#ifndef LEMON_BITS_SOLVER_BITS_H
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#define LEMON_BITS_SOLVER_BITS_H
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#include <vector>
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namespace lemon {
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  namespace _solver_bits {
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    class VarIndex {
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    private:
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      struct ItemT {
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        int prev, next;
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        int index;
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      };
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      std::vector<ItemT> items;
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      int first_item, last_item, first_free_item;
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      std::vector<int> cross;
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    public:
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      VarIndex()
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        : first_item(-1), last_item(-1), first_free_item(-1) {
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      }
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      void clear() {
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        first_item = -1;
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        first_free_item = -1;
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        items.clear();
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        cross.clear();
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      }
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      int addIndex(int idx) {
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        int n;
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        if (first_free_item == -1) {
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          n = items.size();
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          items.push_back(ItemT());
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        } else {
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          n = first_free_item;
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          first_free_item = items[n].next;
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          if (first_free_item != -1) {
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            items[first_free_item].prev = -1;
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          }
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        }
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        items[n].index = idx;
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        if (static_cast<int>(cross.size()) <= idx) {
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          cross.resize(idx + 1, -1);
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        }
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        cross[idx] = n;
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        items[n].prev = last_item;
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        items[n].next = -1;
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        if (last_item != -1) {
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          items[last_item].next = n;
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        } else {
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          first_item = n;
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        }
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        last_item = n;
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        return n;
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      }
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      int addIndex(int idx, int n) {
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        while (n >= static_cast<int>(items.size())) {
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          items.push_back(ItemT());
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          items.back().prev = -1;
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          items.back().next = first_free_item;
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          if (first_free_item != -1) {
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            items[first_free_item].prev = items.size() - 1;
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          }
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          first_free_item = items.size() - 1;
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        }
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        if (items[n].next != -1) {
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          items[items[n].next].prev = items[n].prev;
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        }
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        if (items[n].prev != -1) {
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          items[items[n].prev].next = items[n].next;
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        } else {
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          first_free_item = items[n].next;
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        }
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        items[n].index = idx;
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        if (static_cast<int>(cross.size()) <= idx) {
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          cross.resize(idx + 1, -1);
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        }
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        cross[idx] = n;
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        items[n].prev = last_item;
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        items[n].next = -1;
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        if (last_item != -1) {
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          items[last_item].next = n;
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        } else {
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          first_item = n;
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        }
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        last_item = n;
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        return n;
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      }
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      void eraseIndex(int idx) {
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        int n = cross[idx];
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        if (items[n].prev != -1) {
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          items[items[n].prev].next = items[n].next;
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        } else {
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          first_item = items[n].next;
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        }
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        if (items[n].next != -1) {
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          items[items[n].next].prev = items[n].prev;
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        } else {
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          last_item = items[n].prev;
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        }
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        if (first_free_item != -1) {
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          items[first_free_item].prev = n;
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        }
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        items[n].next = first_free_item;
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        items[n].prev = -1;
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        first_free_item = n;
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        while (!cross.empty() && cross.back() == -1) {
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          cross.pop_back();
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        }
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      }
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      int maxIndex() const {
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        return cross.size() - 1;
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      }
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      void shiftIndices(int idx) {
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        for (int i = idx + 1; i < static_cast<int>(cross.size()); ++i) {
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          cross[i - 1] = cross[i];
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          if (cross[i] != -1) {
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            --items[cross[i]].index;
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          }
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        }
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        cross.back() = -1;
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        cross.pop_back();
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        while (!cross.empty() && cross.back() == -1) {
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          cross.pop_back();
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        }
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      }
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      void relocateIndex(int idx, int jdx) {
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        cross[idx] = cross[jdx];
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        items[cross[jdx]].index = idx;
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        cross[jdx] = -1;
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        while (!cross.empty() && cross.back() == -1) {
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          cross.pop_back();
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        }
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      }
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      int operator[](int idx) const {
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        return cross[idx];
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      }
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      int operator()(int fdx) const {
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        return items[fdx].index;
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      }
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      void firstItem(int& fdx) const {
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        fdx = first_item;
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      }
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      void nextItem(int& fdx) const {
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        fdx = items[fdx].next;
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      }
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    };
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  }
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}
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#endif