#ifndef EXAMPLES_UNION_FIND_HPP
#define EXAMPLES_UNION_FIND_HPP
#include <algorithm>
#include <vector>
/**
* @brief a Union-Find
* @note most operations in $O(\alpha(n))$ where $\alpha(n)$ is the inverse of Ackermann function
* @note implemented with union-by-size + path-compression
*/
struct union_find {
std::vector<int> data;
union_find() = default;
explicit union_find(int n) : data(n, -1) {}
bool is_root(int i) { return data[i] < 0; }
int find_root(int i) { return is_root(i) ? i : (data[i] = find_root(data[i])); }
int tree_size(int i) { return - data[find_root(i)]; }
int unite_trees(int i, int j) {
i = find_root(i); j = find_root(j);
if (i != j) {
if (tree_size(i) < tree_size(j)) std::swap(i, j);
data[i] += data[j];
data[j] = i;
}
return i;
}
bool is_same(int i, int j) { return find_root(i) == find_root(j); }
};
#endif
#line 1 "examples/cpp/union_find.hpp"
#include <algorithm>
#include <vector>
/**
* @brief a Union-Find
* @note most operations in $O(\alpha(n))$ where $\alpha(n)$ is the inverse of Ackermann function
* @note implemented with union-by-size + path-compression
*/
struct union_find {
std::vector<int> data;
union_find() = default;
explicit union_find(int n) : data(n, -1) {}
bool is_root(int i) { return data[i] < 0; }
int find_root(int i) { return is_root(i) ? i : (data[i] = find_root(data[i])); }
int tree_size(int i) { return - data[find_root(i)]; }
int unite_trees(int i, int j) {
i = find_root(i); j = find_root(j);
if (i != j) {
if (tree_size(i) < tree_size(j)) std::swap(i, j);
data[i] += data[j];
data[j] = i;
}
return i;
}
bool is_same(int i, int j) { return find_root(i) == find_root(j); }
};