28 lines
702 B
C++
28 lines
702 B
C++
#include <vector>
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using namespace std;
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class UFDS {
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private: int num_sets; vector<int> p, rank, size;
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public:
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UFDS(int N) {
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num_sets = N;
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p.assign(N, 0);
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for (int i = 0; i < N; i++) p[i] = i;
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rank.assign(N, 0);
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size.assign(N, 1);
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}
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int find_set(int i) { return (p[i] == i) ? i : (p[i] = find_set(p[i])); }
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bool same_set(int i, int j) { return find_set(i) == find_set(j); }
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int sets() { return num_sets; }
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int size_set(int i) { return size[find_set(i)]; }
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void union_set(int i, int j) {
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if (same_set(i, j)) return;
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int x = find_set(i), y = find_set(j);
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if (rank[x] > rank[y]) swap(x, y);
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p[x] = y;
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if (rank[x] == rank[y]) rank[y]++;
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size[y] += size[x];
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--num_sets;
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}
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};
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