diff --git a/lemon/bucket_heap.h b/lemon/bucket_heap.h --- a/lemon/bucket_heap.h +++ b/lemon/bucket_heap.h @@ -29,6 +29,30 @@ namespace lemon { + namespace _bucket_heap_bits { + + template + struct DirectionTraits { + static bool less(int left, int right) { + return left < right; + } + static void increase(int& value) { + ++value; + } + }; + + template <> + struct DirectionTraits { + static bool less(int left, int right) { + return left > right; + } + static void increase(int& value) { + --value; + } + }; + + } + /// \ingroup auxdat /// /// \brief A Bucket Heap implementation. @@ -45,7 +69,7 @@ /// to handle the cross references. /// \param minimize If the given parameter is true then the heap gives back /// the lowest priority. - template + template class BucketHeap { public: @@ -58,6 +82,12 @@ /// \e typedef _ItemIntMap ItemIntMap; + private: + + typedef _bucket_heap_bits::DirectionTraits Direction; + + public: + /// \brief Type to represent the items states. /// /// Each Item element have a state associated to it. It may be "in heap", @@ -161,7 +191,7 @@ index[i] = idx; data.push_back(BucketItem(i, p)); lace(idx); - if (p < minimal) { + if (Direction::less(p, minimal)) { minimal = p; } } @@ -172,7 +202,7 @@ /// \pre The heap must be nonempty. Item top() const { while (first[minimal] == -1) { - ++minimal; + Direction::increase(minimal); } return data[first[minimal]].item; } @@ -183,7 +213,7 @@ /// \pre The heap must be nonempty. Prio prio() const { while (first[minimal] == -1) { - ++minimal; + Direction::increase(minimal); } return minimal; } @@ -194,7 +224,7 @@ /// \pre The heap must be non-empty. void pop() { while (first[minimal] == -1) { - ++minimal; + Direction::increase(minimal); } int idx = first[minimal]; index[data[idx].item] = -2; @@ -235,11 +265,11 @@ void set(const Item &i, const Prio &p) { int idx = index[i]; if (idx < 0) { - push(i,p); - } else if (p > data[idx].value) { + push(i, p); + } else if (Direction::less(p, data[idx].value)) { + decrease(i, p); + } else { increase(i, p); - } else { - decrease(i, p); } } @@ -254,7 +284,7 @@ int idx = index[i]; unlace(idx); data[idx].value = p; - if (p < minimal) { + if (Direction::less(p, minimal)) { minimal = p; } lace(idx); @@ -328,193 +358,6 @@ }; // class BucketHeap - - template - class BucketHeap<_ItemIntMap, false> { - - public: - typedef typename _ItemIntMap::Key Item; - typedef int Prio; - typedef std::pair Pair; - typedef _ItemIntMap ItemIntMap; - - enum State { - IN_HEAP = 0, - PRE_HEAP = -1, - POST_HEAP = -2 - }; - - public: - - explicit BucketHeap(ItemIntMap &_index) : index(_index), maximal(-1) {} - - int size() const { return data.size(); } - bool empty() const { return data.empty(); } - - void clear() { - data.clear(); first.clear(); maximal = -1; - } - - private: - - void relocate_last(int idx) { - if (idx + 1 != int(data.size())) { - data[idx] = data.back(); - if (data[idx].prev != -1) { - data[data[idx].prev].next = idx; - } else { - first[data[idx].value] = idx; - } - if (data[idx].next != -1) { - data[data[idx].next].prev = idx; - } - index[data[idx].item] = idx; - } - data.pop_back(); - } - - void unlace(int idx) { - if (data[idx].prev != -1) { - data[data[idx].prev].next = data[idx].next; - } else { - first[data[idx].value] = data[idx].next; - } - if (data[idx].next != -1) { - data[data[idx].next].prev = data[idx].prev; - } - } - - void lace(int idx) { - if (int(first.size()) <= data[idx].value) { - first.resize(data[idx].value + 1, -1); - } - data[idx].next = first[data[idx].value]; - if (data[idx].next != -1) { - data[data[idx].next].prev = idx; - } - first[data[idx].value] = idx; - data[idx].prev = -1; - } - - public: - - void push(const Pair& p) { - push(p.first, p.second); - } - - void push(const Item &i, const Prio &p) { - int idx = data.size(); - index[i] = idx; - data.push_back(BucketItem(i, p)); - lace(idx); - if (data[idx].value > maximal) { - maximal = data[idx].value; - } - } - - Item top() const { - while (first[maximal] == -1) { - --maximal; - } - return data[first[maximal]].item; - } - - Prio prio() const { - while (first[maximal] == -1) { - --maximal; - } - return maximal; - } - - void pop() { - while (first[maximal] == -1) { - --maximal; - } - int idx = first[maximal]; - index[data[idx].item] = -2; - unlace(idx); - relocate_last(idx); - } - - void erase(const Item &i) { - int idx = index[i]; - index[data[idx].item] = -2; - unlace(idx); - relocate_last(idx); - } - - Prio operator[](const Item &i) const { - int idx = index[i]; - return data[idx].value; - } - - void set(const Item &i, const Prio &p) { - int idx = index[i]; - if (idx < 0) { - push(i,p); - } else if (p > data[idx].value) { - decrease(i, p); - } else { - increase(i, p); - } - } - - void decrease(const Item &i, const Prio &p) { - int idx = index[i]; - unlace(idx); - data[idx].value = p; - if (p > maximal) { - maximal = p; - } - lace(idx); - } - - void increase(const Item &i, const Prio &p) { - int idx = index[i]; - unlace(idx); - data[idx].value = p; - lace(idx); - } - - State state(const Item &i) const { - int idx = index[i]; - if (idx >= 0) idx = 0; - return State(idx); - } - - void state(const Item& i, State st) { - switch (st) { - case POST_HEAP: - case PRE_HEAP: - if (state(i) == IN_HEAP) { - erase(i); - } - index[i] = st; - break; - case IN_HEAP: - break; - } - } - - private: - - struct BucketItem { - BucketItem(const Item& _item, int _value) - : item(_item), value(_value) {} - - Item item; - int value; - - int prev, next; - }; - - ItemIntMap& index; - std::vector first; - std::vector data; - mutable int maximal; - - }; // class BucketHeap - /// \ingroup auxdat /// /// \brief A Simplified Bucket Heap implementation. @@ -524,7 +367,7 @@ /// and simplier data structure than the BucketHeap. The main /// difference is that the BucketHeap stores for every key a double /// linked list while this class stores just simple lists. In the - /// other way it does not supports erasing each elements just the + /// other way it does not support erasing each elements just the /// minimal and it does not supports key increasing, decreasing. /// /// \param _ItemIntMap A read and writable Item int map, used internally @@ -542,6 +385,12 @@ typedef std::pair Pair; typedef _ItemIntMap ItemIntMap; + private: + + typedef _bucket_heap_bits::DirectionTraits Direction; + + public: + /// \brief Type to represent the items states. /// /// Each Item element have a state associated to it. It may be "in heap", @@ -614,7 +463,7 @@ if (p >= int(first.size())) first.resize(p + 1, -1); data[idx].next = first[p]; first[p] = idx; - if (p < minimal) { + if (Direction::less(p, minimal)) { minimal = p; } ++num; @@ -626,7 +475,7 @@ /// \pre The heap must be nonempty. Item top() const { while (first[minimal] == -1) { - ++minimal; + Direction::increase(minimal); } return data[first[minimal]].item; } @@ -637,7 +486,7 @@ /// \pre The heap must be nonempty. Prio prio() const { while (first[minimal] == -1) { - ++minimal; + Direction::increase(minimal); } return minimal; } @@ -648,7 +497,7 @@ /// \pre The heap must be non-empty. void pop() { while (first[minimal] == -1) { - ++minimal; + Direction::increase(minimal); } int idx = first[minimal]; index[data[idx].item] = -2; @@ -711,121 +560,6 @@ }; // class SimpleBucketHeap - template - class SimpleBucketHeap<_ItemIntMap, false> { - - public: - typedef typename _ItemIntMap::Key Item; - typedef int Prio; - typedef std::pair Pair; - typedef _ItemIntMap ItemIntMap; - - enum State { - IN_HEAP = 0, - PRE_HEAP = -1, - POST_HEAP = -2 - }; - - public: - - explicit SimpleBucketHeap(ItemIntMap &_index) - : index(_index), free(-1), num(0), maximal(0) {} - - int size() const { return num; } - - bool empty() const { return num == 0; } - - void clear() { - data.clear(); first.clear(); free = -1; num = 0; maximal = 0; - } - - void push(const Pair& p) { - push(p.first, p.second); - } - - void push(const Item &i, const Prio &p) { - int idx; - if (free == -1) { - idx = data.size(); - data.push_back(BucketItem(i)); - } else { - idx = free; - free = data[idx].next; - data[idx].item = i; - } - index[i] = idx; - if (p >= int(first.size())) first.resize(p + 1, -1); - data[idx].next = first[p]; - first[p] = idx; - if (p > maximal) { - maximal = p; - } - ++num; - } - - Item top() const { - while (first[maximal] == -1) { - --maximal; - } - return data[first[maximal]].item; - } - - Prio prio() const { - while (first[maximal] == -1) { - --maximal; - } - return maximal; - } - - void pop() { - while (first[maximal] == -1) { - --maximal; - } - int idx = first[maximal]; - index[data[idx].item] = -2; - first[maximal] = data[idx].next; - data[idx].next = free; - free = idx; - --num; - } - - Prio operator[](const Item &i) const { - for (int k = 0; k < first.size(); ++k) { - int idx = first[k]; - while (idx != -1) { - if (data[idx].item == i) { - return k; - } - idx = data[idx].next; - } - } - return -1; - } - - State state(const Item &i) const { - int idx = index[i]; - if (idx >= 0) idx = 0; - return State(idx); - } - - private: - - struct BucketItem { - BucketItem(const Item& _item) : item(_item) {} - - Item item; - - int next; - }; - - ItemIntMap& index; - std::vector first; - std::vector data; - int free, num; - mutable int maximal; - - }; - } #endif