C++ 程序实现分离集合数据结构
分离集合基本上作为一组集合,其中一项不会在多于一个集合中。它支持子集上的并集和查找操作。
查找():用于查找特定元素位于哪个子集并在该特定集合中返回代表项。
并集():它将两个不同的子集合并到一个子集中,并且一个集合的代表项变为另一个集合的代表项。
函数和伪码
Begin Assume k is the element makeset(k): k.parent = k. Find(x): If k.parent == k return k. else return Find(k.parent) Union (a,b): Take two set a and b as input. aroot = Find(a) broot = Find(b) aroot.parent = broot End
示例
#include <iostream> #include <vector> #include <unordered_map> using namespace std; class DisjointSet { //to represent disjoint set unordered_map<int, int> parent; public: void makeSet(vector<int> const &wholeset){ //perform makeset operation for (int i : wholeset) // create n disjoint sets (one for each item) parent[i] = i; } int Find(int l) { // Find the root of the set in which element l belongs if (parent[l] == l) // if l is root return l; return Find(parent[l]); // recurs for parent till we find root } void Union(int m, int n) { // perform Union of two subsets m and n int x = Find(m); int y = Find(n); parent[x] = y; } }; void print(vector<int> const &universe, DisjointSet &dis) { for (int i : universe) cout << dis.Find(i) << " "; cout << '\n'; } int main() { vector<int> wholeset = { 6,7,1,2,3 }; // items of whole set DisjointSet dis; //initialize DisjointSet class dis.makeSet(wholeset); // create individual set of the items of wholeset dis.Union(7, 6); // 7,6 are in same set print(wholeset, dis); if (dis.Find(7) == dis.Find(6)) // if they are belong to same set or not. cout<<"Yes"<<endl; else cout<<"No"; if (dis.Find(3) == dis.Find(4)) cout<<"Yes"<<endl; else cout<<"No"; return 0; }
输出
6 6 1 2 3 Yes No
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