#include <utils/utils.h>
#include <utils/disjoint_set.h>
int disjoint_set_make(struct disjoint_set *set, int max_nodes)
{
int i;
if (max_nodes >= DISJOINT_SET_MAX)
return -1;
set->max_nodes = max_nodes;
for (i = 0; i < max_nodes; i++) {
set->parent[i] = i;
set->rank[i] = 0;
}
return 0;
}
int disjoint_set_find(struct disjoint_set *set, int a)
{
int tmp, root = a;
while (set->parent[root] != root)
root = set->parent[root];
while (set->parent[a] != root) {
tmp = set->parent[a];
set->parent[a] = root;
a = tmp;
}
return root;
}
void disjoint_set_union(struct disjoint_set *set, int a, int b)
{
a = disjoint_set_find(set, a);
b = disjoint_set_find(set, b);
if (a == b)
return;
if (set->rank[a] < set->rank[b]) {
int tmp;
tmp = a;
a = b;
b = tmp;
}
set->parent[b] = a;
if (set->rank[a] == set->rank[b])
set->rank[a] += 1;
}
int disjoint_set_num_roots(struct disjoint_set *set)
{
int i, roots = 0;
for (i = 0; i < set->max_nodes; i++) {
if (set->parent[i] == i)
roots++;
}
return roots;
}