170 lines
5.2 KiB
C++
170 lines
5.2 KiB
C++
/******************************************************************************************[Heap.h]
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MiniSat -- Copyright (c) 2003-2006, Niklas Een, Niklas Sorensson
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Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
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associated documentation files (the "Software"), to deal in the Software without restriction,
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including without limitation the rights to use, copy, modify, merge, publish, distribute,
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sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all copies or
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substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
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NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
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OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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**************************************************************************************************/
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#ifndef Heap_h
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#define Heap_h
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#include "Vec.h"
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//=================================================================================================
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// A heap implementation with support for decrease/increase key.
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template<class Comp>
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class Heap {
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Comp lt;
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vec<int> heap; // heap of ints
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vec<int> indices; // int -> index in heap
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// Index "traversal" functions
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static inline int left (int i) { return i*2+1; }
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static inline int right (int i) { return (i+1)*2; }
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static inline int parent(int i) { return (i-1) >> 1; }
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inline void percolateUp(int i)
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{
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int x = heap[i];
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while (i != 0 && lt(x, heap[parent(i)])){
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heap[i] = heap[parent(i)];
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indices[heap[i]] = i;
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i = parent(i);
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}
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heap [i] = x;
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indices[x] = i;
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}
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inline void percolateDown(int i)
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{
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int x = heap[i];
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while (left(i) < heap.size()){
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int child = right(i) < heap.size() && lt(heap[right(i)], heap[left(i)]) ? right(i) : left(i);
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if (!lt(heap[child], x)) break;
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heap[i] = heap[child];
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indices[heap[i]] = i;
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i = child;
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}
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heap [i] = x;
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indices[x] = i;
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}
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bool heapProperty (int i) const {
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return i >= heap.size()
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|| ((i == 0 || !lt(heap[i], heap[parent(i)])) && heapProperty(left(i)) && heapProperty(right(i))); }
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public:
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Heap(const Comp& c) : lt(c) { }
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int size () const { return heap.size(); }
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bool empty () const { return heap.size() == 0; }
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bool inHeap (int n) const { return n < indices.size() && indices[n] >= 0; }
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int operator[](int index) const { assert(index < heap.size()); return heap[index]; }
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void decrease (int n) { assert(inHeap(n)); percolateUp(indices[n]); }
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// RENAME WHEN THE DEPRECATED INCREASE IS REMOVED.
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void increase_ (int n) { assert(inHeap(n)); percolateDown(indices[n]); }
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void insert(int n)
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{
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indices.growTo(n+1, -1);
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assert(!inHeap(n));
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indices[n] = heap.size();
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heap.push(n);
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percolateUp(indices[n]);
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}
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int removeMin()
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{
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int x = heap[0];
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heap[0] = heap.last();
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indices[heap[0]] = 0;
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indices[x] = -1;
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heap.pop();
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if (heap.size() > 1) percolateDown(0);
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return x;
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}
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void clear(bool dealloc = false)
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{
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for (int i = 0; i < heap.size(); i++)
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indices[heap[i]] = -1;
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#ifdef NDEBUG
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for (int i = 0; i < indices.size(); i++)
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assert(indices[i] == -1);
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#endif
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heap.clear(dealloc);
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}
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// Fool proof variant of insert/decrease/increase
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void update (int n)
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{
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if (!inHeap(n))
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insert(n);
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else {
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percolateUp(indices[n]);
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percolateDown(indices[n]);
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}
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}
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// Delete elements from the heap using a given filter function (-object).
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// *** this could probaly be replaced with a more general "buildHeap(vec<int>&)" method ***
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template <class F>
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void filter(const F& filt) {
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int i,j;
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for (i = j = 0; i < heap.size(); i++)
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if (filt(heap[i])){
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heap[j] = heap[i];
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indices[heap[i]] = j++;
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}else
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indices[heap[i]] = -1;
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heap.shrink(i - j);
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for (int i = heap.size() / 2 - 1; i >= 0; i--)
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percolateDown(i);
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assert(heapProperty());
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}
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// DEBUG: consistency checking
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bool heapProperty() const {
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return heapProperty(1); }
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// COMPAT: should be removed
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void setBounds (int n) { }
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void increase (int n) { decrease(n); }
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int getmin () { return removeMin(); }
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};
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//=================================================================================================
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#endif
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