84 lines
1.5 KiB
C++
84 lines
1.5 KiB
C++
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template<unsigned B>
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class unionfind
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{
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unsigned n_sets;
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basedvector<unsigned, B> parent;
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public:
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unionfind (unsigned size);
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unionfind (const unionfind &u) : n_sets(u.n_sets), parent(u.parent) { }
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unionfind (copy, const unionfind &u) : n_sets(u.n_sets), parent(COPY, u.parent) { }
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unionfind (reader &r);
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~unionfind () { }
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unsigned num_sets () const { return n_sets; }
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void clear ();
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void join (unsigned x, unsigned y);
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unsigned find (unsigned x);
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void write_self (writer &w) const;
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};
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template<unsigned B>
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unionfind<B>::unionfind (unsigned size)
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: n_sets(size),
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parent(size)
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{
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for (unsigned i = 0; i < size; i ++)
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parent[i + B] = i + B;
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}
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template<unsigned B>
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unionfind<B>::unionfind (reader &r)
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{
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read (r, n_sets);
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read (r, parent);
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}
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template<unsigned B> void
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unionfind<B>::clear ()
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{
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unsigned size = parent.size ();
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n_sets = size;
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for (unsigned i = 0; i < size; i ++)
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parent[i + B] = i + B;
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}
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template<unsigned B> void
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unionfind<B>::join (unsigned x, unsigned y)
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{
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unsigned xp = find (x),
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yp = find (y);
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if (xp != yp)
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{
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n_sets --;
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parent[yp] = xp;
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}
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}
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template<unsigned B> unsigned
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unionfind<B>::find (unsigned x)
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{
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unsigned p = parent[x];
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while (parent[p] != p)
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p = parent[p];
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while (x != p)
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{
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unsigned xp = parent[x];
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parent[x] = p;
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x = xp;
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}
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return p;
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}
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template<unsigned B> void
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unionfind<B>::write_self (writer &w) const
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{
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write (w, n_sets);
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write (w, parent);
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}
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