并查集

/* UnionFindSet.h 并查集，非递归方法，含路径压缩，数组从0开始 合并时，前者合并入后者，不区分大小 */ #include <iostream> using namespace std; #define MAXN 30005 class UFS { public: int n; int father[MAXN+1];//集合根结点 int rank[MAXN+1]; //集合中点的个数 int depth[MAXN+1]; //每个结点改变一次所属的集合，增加一些值 public: UFS(int size = MAXN); void clear(); int Find(int x); //a并入b中，不区分大小 //value表示：如果a并入b中，a中r所有元素能获得的值 void Union(int a, int b, int value = 0); }; UFS::UFS(int size):n(size) { //必须从0开始 for(int i = 0; i <= n; i++) { father[i] = i; rank[i] = 1; depth[i] = 0; } } void UFS::clear() { for(int i = 0; i <= n; i++) { father[i] = i; rank[i] = 1; depth[i] = 0; } } int UFS::Find(int x) { int temp = x,sum = 0,ans; while(temp != father[temp]) { sum = sum + depth[temp]; temp = father[temp]; } ans = temp; while(x != ans) { sum -= depth[x]; depth[x] += sum; temp = father[x]; father[x] = ans; x = temp; } return ans; } void UFS::Union(int a, int b,int value) { int x = Find(a); int y = Find(b); if(x == y) return ; if(value >= 0) depth[x] = value; else depth[x] = rank[y]; rank[y] += rank[x]; father[x] = y; }