42 lines
1003 B
Rust
42 lines
1003 B
Rust
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import option.none;
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import option.some;
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// A very naive implementation of union-find with unsigned integer nodes.
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tag node {
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elem(uint, option.t[uint]);
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}
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type ufind = rec(mutable vec[mutable node] nodes);
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fn make() -> ufind {
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let vec[mutable node] v = vec(mutable elem(0u, none[uint]));
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_vec.pop[mutable node](v); // FIXME: botch
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ret rec(mutable nodes=v);
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}
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fn make_set(&ufind ufnd, uint n) {
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ufnd.nodes += vec(mutable elem(n, none[uint]));
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}
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fn find(&ufind ufnd, uint n) -> uint {
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alt (ufnd.nodes.(n)) {
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case (elem(_, ?parent_opt)) {
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alt (parent_opt) {
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case (none[uint]) { ret n; }
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case (some[uint](?m)) {
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// TODO: "be"
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ret find(ufnd, m);
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}
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}
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}
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}
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}
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fn union(&ufind ufnd, uint m, uint n) {
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auto m_root = find(ufnd, m);
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auto n_root = find(ufnd, n);
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auto ptr = some[uint](n_root);
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ufnd.nodes.(m_root) = elem(m_root, ptr);
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}
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