并查集的模拟实现

简化版本

class UnionFindSet
{
public:UnionFindSet(size_t n):_ufs(n, -1){}void Union(int x1, int x2){int root1 = FindRoot(x1);int root2 = FindRoot(x2);// 如果本身就在一个集合就没必要合并了if (root1 == root2)return;// 控制数据量小的往大的集合合并if (abs(_ufs[root1]) < abs(_ufs[root2]))swap(root1, root2);_ufs[root1] += _ufs[root2];_ufs[root2] = root1;}int FindRoot(int x){int root = x;while (_ufs[root] >= 0){root = _ufs[root];}// 路径压缩while (_ufs[x] >= 0){int parent = _ufs[x];_ufs[x] = root;x = parent;}return root;}bool InSet(int x1, int x2){return FindRoot(x1) == FindRoot(x2);}size_t SetSize(){size_t size = 0;for (size_t i = 0; i < _ufs.size(); ++i){if (_ufs[i] < 0){++size;}}return size;}private:vector<int> _ufs;
};