Documentation

Std.Data.BinomialHeap.Basic

A HeapNode is one of the internal nodes of the binomial heap. It is always a perfect binary tree, with the depth of the tree stored in the Heap. However the interpretation of the two pointers is different: we view the child as going to the first child of this node, and sibling goes to the next sibling of this tree. So it actually encodes a forest where each node has children node.child, node.child.sibling, node.child.sibling.sibling, etc.

Each edge in this forest denotes a le a b relation that has been checked, so the root is smaller than everything else under it.

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    • Std.BinomialHeap.Imp.instReprHeapNode = { reprPrec := Std.BinomialHeap.Imp.reprHeapNode✝ }

    The "real size" of the node, counting up how many values of type α are stored. This is O(n) and is intended mainly for specification purposes. For a well formed HeapNode the size is always 2^n - 1 where n is the depth.

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      A node containing a single element a.

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        O(log n). The rank, or the number of trees in the forest. It is also the depth of the forest.

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          inductive Std.BinomialHeap.Imp.Heap (α : Type u) :

          A Heap is the top level structure in a binomial heap. It consists of a forest of HeapNodes with strictly increasing ranks.

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            instance Std.BinomialHeap.Imp.instReprHeap :
            {α : Type u_1} → [inst : Repr α] → Repr (Std.BinomialHeap.Imp.Heap α)
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            • Std.BinomialHeap.Imp.instReprHeap = { reprPrec := Std.BinomialHeap.Imp.reprHeap✝ }

            O(n). The "real size" of the heap, counting up how many values of type α are stored. This is intended mainly for specification purposes. Prefer Heap.size, which is the same for well formed heaps.

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              O(log n). The number of elements in the heap.

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                O(1). Is the heap empty?

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                  O(1). The heap containing a single value a.

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                    O(1). Auxiliary for Heap.merge: Is the minimum rank in Heap strictly larger than n?

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                      O(log n). The number of trees in the forest.

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                        def Std.BinomialHeap.Imp.combine {α : Type u_1} (le : ααBool) (a₁ : α) (a₂ : α) (n₁ : Std.BinomialHeap.Imp.HeapNode α) (n₂ : Std.BinomialHeap.Imp.HeapNode α) :

                        O(1). Auxiliary for Heap.merge: combines two heap nodes of the same rank into one with the next larger rank.

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                          Merge two forests of binomial trees. The forests are assumed to be ordered by rank and merge maintains this invariant.

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                            O(log n). Convert a HeapNode to a Heap by reversing the order of the nodes along the sibling spine.

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                              def Std.BinomialHeap.Imp.Heap.headD {α : Type u_1} (le : ααBool) (a : α) :

                              O(log n). Get the smallest element in the heap, including the passed in value a.

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                                def Std.BinomialHeap.Imp.Heap.head? {α : Type u_1} (le : ααBool) :

                                O(log n). Get the smallest element in the heap, if it has an element.

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                                  structure Std.BinomialHeap.Imp.FindMin (α : Type u_1) :
                                  Type u_1

                                  The return type of FindMin, which encodes various quantities needed to reconstruct the tree in deleteMin.

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                                    O(log n). Find the minimum element, and return a data structure FindMin with information needed to reconstruct the rest of the binomial heap.

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                                      O(log n). Find and remove the the minimum element from the binomial heap.

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                                        O(log n). Get the tail of the binomial heap after removing the minimum element.

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                                          O(log n). Remove the minimum element of the heap.

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                                            def Std.BinomialHeap.Imp.Heap.foldM {m : Type u_1 → Type u_2} {α : Type u_3} {β : Type u_1} [Monad m] (le : ααBool) (s : Std.BinomialHeap.Imp.Heap α) (init : β) (f : βαm β) :
                                            m β

                                            O(n log n). Monadic fold over the elements of a heap in increasing order, by repeatedly pulling the minimum element out of the heap.

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                                              def Std.BinomialHeap.Imp.Heap.fold {α : Type u_1} {β : Type u_2} (le : ααBool) (s : Std.BinomialHeap.Imp.Heap α) (init : β) (f : βαβ) :
                                              β

                                              O(n log n). Fold over the elements of a heap in increasing order, by repeatedly pulling the minimum element out of the heap.

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                                                def Std.BinomialHeap.Imp.Heap.toArray {α : Type u_1} (le : ααBool) (s : Std.BinomialHeap.Imp.Heap α) :

                                                O(n log n). Convert the heap to an array in increasing order.

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                                                  def Std.BinomialHeap.Imp.Heap.toList {α : Type u_1} (le : ααBool) (s : Std.BinomialHeap.Imp.Heap α) :
                                                  List α

                                                  O(n log n). Convert the heap to a list in increasing order.

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                                                    def Std.BinomialHeap.Imp.HeapNode.foldTreeM {m : Type u_1 → Type u_2} {β : Type u_1} {α : Type u_3} [Monad m] (nil : β) (join : αββm β) :

                                                    O(n). Fold a monadic function over the tree structure to accumulate a value.

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                                                      def Std.BinomialHeap.Imp.Heap.foldTreeM {m : Type u_1 → Type u_2} {β : Type u_1} {α : Type u_3} [Monad m] (nil : β) (join : αββm β) :

                                                      O(n). Fold a monadic function over the tree structure to accumulate a value.

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                                                        def Std.BinomialHeap.Imp.Heap.foldTree {β : Type u_1} {α : Type u_2} (nil : β) (join : αβββ) (s : Std.BinomialHeap.Imp.Heap α) :
                                                        β

                                                        O(n). Fold a function over the tree structure to accumulate a value.

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                                                          O(n). Convert the heap to a list in arbitrary order.

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                                                            O(n). Convert the heap to an array in arbitrary order.

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                                                              def Std.BinomialHeap.Imp.HeapNode.WF {α : Type u_1} (le : ααBool) (a : α) :

                                                              The well formedness predicate for a heap node. It asserts that:

                                                              • If a is added at the top to make the forest into a tree, the resulting tree is a le-min-heap (if le is well-behaved)
                                                              • When interpreting child and sibling as left and right children of a binary tree, it is a perfect binary tree with depth r
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                                                                def Std.BinomialHeap.Imp.Heap.WF {α : Type u_1} (le : ααBool) (n : Nat) :

                                                                The well formedness predicate for a binomial heap. It asserts that:

                                                                • It consists of a list of well formed trees with the specified ranks
                                                                • The ranks are in strictly increasing order, and all are at least n
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                                                                  theorem Std.BinomialHeap.Imp.Heap.WF.nil :
                                                                  ∀ {α : Type u_1} {le : ααBool} {n : Nat}, Std.BinomialHeap.Imp.Heap.WF le n Std.BinomialHeap.Imp.Heap.nil
                                                                  theorem Std.BinomialHeap.Imp.Heap.WF.of_le {n : Nat} {n' : Nat} :
                                                                  ∀ {α : Type u_1} {le : ααBool} {s : Std.BinomialHeap.Imp.Heap α}, n n'Std.BinomialHeap.Imp.Heap.WF le n' sStd.BinomialHeap.Imp.Heap.WF le n s
                                                                  structure Std.BinomialHeap.Imp.FindMin.WF {α : Type u_1} (le : ααBool) (res : Std.BinomialHeap.Imp.FindMin α) :

                                                                  The well formedness predicate for a FindMin value. This is not actually a predicate, as it contains an additional data value rank corresponding to the rank of the returned node, which is omitted from findMin.

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                                                                    The conditions under which findMin is well-formed.

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                                                                      def Std.BinomialHeap (α : Type u) (le : ααBool) :

                                                                      A binomial heap is a data structure which supports the following primary operations:

                                                                      The first two operations are known as a "priority queue", so this could be called a "mergeable priority queue". The standard choice for a priority queue is a binary heap, which supports insert and deleteMin in O(log n), but merge is O(n). With a BinomialHeap, all three operations are O(log n).

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                                                                        def Std.mkBinomialHeap (α : Type u) (le : ααBool) :

                                                                        O(1). Make a new empty binomial heap.

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                                                                          def Std.BinomialHeap.empty {α : Type u} {le : ααBool} :

                                                                          O(1). Make a new empty binomial heap.

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                                                                            • Std.BinomialHeap.instEmptyCollectionBinomialHeap = { emptyCollection := Std.BinomialHeap.empty }
                                                                            instance Std.BinomialHeap.instInhabitedBinomialHeap {α : Type u} {le : ααBool} :
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                                                                            • Std.BinomialHeap.instInhabitedBinomialHeap = { default := Std.BinomialHeap.empty }
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                                                                            def Std.BinomialHeap.isEmpty {α : Type u} {le : ααBool} (b : Std.BinomialHeap α le) :

                                                                            O(1). Is the heap empty?

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                                                                              def Std.BinomialHeap.size {α : Type u} {le : ααBool} (b : Std.BinomialHeap α le) :

                                                                              O(log n). The number of elements in the heap.

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                                                                                def Std.BinomialHeap.singleton {α : Type u} {le : ααBool} (a : α) :

                                                                                O(1). Make a new heap containing a.

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                                                                                  def Std.BinomialHeap.merge {α : Type u} {le : ααBool} :

                                                                                  O(log n). Merge the contents of two heaps.

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                                                                                    def Std.BinomialHeap.insert {α : Type u} {le : ααBool} (a : α) (h : Std.BinomialHeap α le) :

                                                                                    O(log n). Add element a to the given heap h.

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                                                                                      def Std.BinomialHeap.ofList {α : Type u} (le : ααBool) (as : List α) :

                                                                                      O(n log n). Construct a heap from a list by inserting all the elements.

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                                                                                        def Std.BinomialHeap.ofArray {α : Type u} (le : ααBool) (as : Array α) :

                                                                                        O(n log n). Construct a heap from a list by inserting all the elements.

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                                                                                          def Std.BinomialHeap.deleteMin {α : Type u} {le : ααBool} (b : Std.BinomialHeap α le) :

                                                                                          O(log n). Remove and return the minimum element from the heap.

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                                                                                            instance Std.BinomialHeap.instStreamBinomialHeap {α : Type u} {le : ααBool} :
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                                                                                            • Std.BinomialHeap.instStreamBinomialHeap = { next? := Std.BinomialHeap.deleteMin }
                                                                                            def Std.BinomialHeap.forIn {α : Type u} {le : ααBool} {m : Type u_1 → Type u_2} {β : Type u_1} [Monad m] (b : Std.BinomialHeap α le) (x : β) (f : αβm (ForInStep β)) :
                                                                                            m β

                                                                                            O(n log n). Implementation of for x in (b : BinomialHeap α le) ... notation, which iterates over the elements in the heap in increasing order.

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                                                                                              instance Std.BinomialHeap.instForInBinomialHeap {α : Type u} {le : ααBool} {m : Type u_1 → Type u_2} :
                                                                                              ForIn m (Std.BinomialHeap α le) α
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                                                                                              • Std.BinomialHeap.instForInBinomialHeap = { forIn := fun {β : Type u_1} [Monad m] => Std.BinomialHeap.forIn }
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                                                                                              def Std.BinomialHeap.head? {α : Type u} {le : ααBool} (b : Std.BinomialHeap α le) :

                                                                                              O(log n). Returns the smallest element in the heap, or none if the heap is empty.

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                                                                                                def Std.BinomialHeap.head! {α : Type u} {le : ααBool} [Inhabited α] (b : Std.BinomialHeap α le) :
                                                                                                α

                                                                                                O(log n). Returns the smallest element in the heap, or panics if the heap is empty.

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                                                                                                  def Std.BinomialHeap.headI {α : Type u} {le : ααBool} [Inhabited α] (b : Std.BinomialHeap α le) :
                                                                                                  α

                                                                                                  O(log n). Returns the smallest element in the heap, or default if the heap is empty.

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                                                                                                    def Std.BinomialHeap.tail? {α : Type u} {le : ααBool} (b : Std.BinomialHeap α le) :

                                                                                                    O(log n). Removes the smallest element from the heap, or none if the heap is empty.

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                                                                                                      def Std.BinomialHeap.tail {α : Type u} {le : ααBool} (b : Std.BinomialHeap α le) :

                                                                                                      O(log n). Removes the smallest element from the heap, if possible.

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                                                                                                        def Std.BinomialHeap.foldM {α : Type u} {le : ααBool} {m : Type u_1 → Type u_2} {β : Type u_1} [Monad m] (b : Std.BinomialHeap α le) (init : β) (f : βαm β) :
                                                                                                        m β

                                                                                                        O(n log n). Monadic fold over the elements of a heap in increasing order, by repeatedly pulling the minimum element out of the heap.

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                                                                                                          def Std.BinomialHeap.fold {α : Type u} {le : ααBool} {β : Type u_1} (b : Std.BinomialHeap α le) (init : β) (f : βαβ) :
                                                                                                          β

                                                                                                          O(n log n). Fold over the elements of a heap in increasing order, by repeatedly pulling the minimum element out of the heap.

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                                                                                                            def Std.BinomialHeap.toList {α : Type u} {le : ααBool} (b : Std.BinomialHeap α le) :
                                                                                                            List α

                                                                                                            O(n log n). Convert the heap to a list in increasing order.

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                                                                                                              def Std.BinomialHeap.toArray {α : Type u} {le : ααBool} (b : Std.BinomialHeap α le) :

                                                                                                              O(n log n). Convert the heap to an array in increasing order.

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                                                                                                                def Std.BinomialHeap.toListUnordered {α : Type u} {le : ααBool} (b : Std.BinomialHeap α le) :
                                                                                                                List α

                                                                                                                O(n). Convert the heap to a list in arbitrary order.

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                                                                                                                  def Std.BinomialHeap.toArrayUnordered {α : Type u} {le : ααBool} (b : Std.BinomialHeap α le) :

                                                                                                                  O(n). Convert the heap to an array in arbitrary order.

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