52 lines
1.3 KiB
C
52 lines
1.3 KiB
C
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#pragma once
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#include <vector>
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#include <cstddef>
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namespace nse
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{
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namespace util
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{
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// Represents a union-find data structure (disjoint sets).
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class UnionFind
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{
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// Node is root iff parent index == index
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public:
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typedef unsigned int index_t;
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// Saves the entire structure to a file for later usage
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void SaveToFile(const char* filename) const;
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// Returns the number of entries
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std::size_t size() const;
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// Loads the entire structure from a file. Existing data in the structure is overridden.
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void LoadFromFile(const char* filename);
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// Adds an item to the structure
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void AddItem();
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void AddItems(std::size_t count);
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void Clear();
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// Finds the set representative for a given entry. Two entries are in the same set
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// iff they have the same set representative.
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index_t GetRepresentative(index_t index);
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// Merges the sets of the two specified entries. Returns the new root.
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index_t Merge(index_t i1, index_t i2);
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// Merges the sets of the two specified entries, such that the specified entry will be the new root of the subtree.
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//newRoot must already be the representative of itself.
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void MergeWithPredefinedRoot(index_t newRoot, index_t i);
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private:
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void ConcreteMerge(index_t newRoot, index_t child);
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std::vector<index_t> parentIndices;
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std::vector<unsigned int> ranks;
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};
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}
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}
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