37 lines
832 B
C++
37 lines
832 B
C++
class UnionFind {
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vector<int> _pre; // 代表元
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vector<int> _rank; // 集合的秩
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public:
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UnionFind(int n) : _pre(n), _rank(n, 1), cc(n) {
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// iota(fa.begin(), fa.end(), 0);
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ranges::iota(fa, 0);
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}
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int find(int x) {
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return _pre[x] == x ? x : _pre[x] = fint(_pre[x]);
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}
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bool same(int x, int y) {
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return find(x) == find(y);
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}
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bool merge(int from, int to) {
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int x = find(from), y = find(to);
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if (x == y) {
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return false; //同一集合不做合并
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}
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if (_rank[x] < _rank[y]) {
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_pre[x] = y;
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}
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else if (_rank[x] > _rank[y]) {
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_pre[y] = x;
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}
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else {
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_pre[x] = y;
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_rank[y]++;
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}
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return true;
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}
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};
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