C++实现并查集

 #include  #include  #include  using namespace std; class UnionFind{ private: vector parent; int count; //优化，记录p和q所在组的深度，在合并时将深度小的结点的根指向深度大的结点的根 vector rank; public: UnionFind(int count){ parent.resize(count); rank.resize(count); this->count = count; fo<mark style="color:transparent">来源gaodaimacom搞#代%码网</mark>r(int i = 0; i = 0 && p <count); if(p != parent[p]) parent[p] = find(parent[p]); return parent[p]; } bool isConnected(int p, int q){ return find(p) == find(q); } void unionElement(int p, int q){ int pRoot = find(p), qRoot = find(q); if(pRoot == qRoot) return; if(rank[pRoot] <rank[qRoot]) parent[pRoot] = qRoot; else if(rank[qRoot] <rank[pRoot]) parent[qRoot] = pRoot; else{ //两者的rank相等 parent[pRoot] = qRoot; rank[qRoot] += 1; } } };

 #include  using namespace std; class UF  { //cnt is the number of disjoint sets. //id is an array that records distinct identity of each set,when two sets are merged ,their id will be same. //sz is an array that records the child number of each set including the set self. int *id, cnt, *sz; public: // Create an empty union find data structure with N isolated sets. UF(int N)  { cnt = N; id = new int[N]; sz = new int[N]; for (int i = 0; i<N; i++) { id[i] = i; sz[i] = 1; } } ~UF() { delete[] id; delete[] sz; } // Return the id of component corresponding to object p. int find(int p) { if (p != id[p]){ id[p] = find(id[p]); } return id[p]; } // Replace sets containing x and y with their union. void merge(int x, int y) { int i = find(x); int j = find(y); if (i == j) return; // make smaller root point to larger one if (sz[i] <sz[j]) { id[i] = j; sz[j] += sz[i]; } else { id[j] = i; sz[i] += sz[j]; } cnt--; } // Are objects x and y in the same set? bool connected(int x, int y)  { return find(x) == find(y); } // Return the number of disjoint sets. int count() { return cnt; } }; void main(){ UF test(5); test.merge(2, 3); test.merge(3, 4); cout << test.find(4); cout << test.count(); }