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union_find.h
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/*
* union-find header.
* written by Shuangquan Li, [email protected]
* created on 2015-12-31
*/
#ifndef __UNION_FIND_H__
#define __UNION_FIND_H__
template<int n> class union_find {
int r[n], c[n];
public:
union_find() { clear(); }
void clear() {
for (int i = 0; i < n; ++i) {
r[i] = i;
c[i] = 1;
}
}
int find(int x) { return x == r[x] ? x : r[x] = find(r[x]); }
void merge(int u, int v) {
int ru = find(u);
int rv = find(v);
if (ru == rv) return;
if (c[ru] < c[rv]) swap(ru, rv);
r[rv] = ru;
c[ru] += c[rv];
}
bool is_merged(int x, int y) { return find(x) == find(y); }
//check_merge
bool cmerge(int u, int v) {
int ru = find(u);
int rv = find(v);
if (ru == rv) return false;
if (c[ru] < c[rv]) swap(ru, rv);
r[rv] = ru;
c[ru] += c[rv];
return true;
}
int size(int x) { return c[find(x)]; }
};
/* eof */
#endif