28 lines
553 B
C++
28 lines
553 B
C++
class quick_union {
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private:
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vector<size_t> c, sz;
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public:
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quick_union(size_t n) : c(n), sz(n) {
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iota(c.begin(), c.end(), 0);
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sz.assign(n, 1);
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}
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size_t query(size_t i) {
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if (c[i] != i) c[i] = query(c[i]);
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return c[i];
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}
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void merge(size_t i, size_t j) {
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sz[query(j)] += sz[query(i)];
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c[query(i)] = query(j);
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}
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bool connected(size_t i, size_t j) {
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return query(i) == query(j);
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}
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size_t query_size(size_t i) {
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return sz[query(i)];
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}
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};
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