-
Notifications
You must be signed in to change notification settings - Fork 0
/
kruskal.cc
65 lines (54 loc) · 968 Bytes
/
kruskal.cc
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
#define MAX_V
#define MAX_E MAX_V*(MAX_V-1)/2
struct edge {int u, v, cost; };
bool comp(const edge& e1, const edge& e2) {
return e1.cost < e2.cost;
}
edge es[MAX_E];
int V, E;
void init(), unite(int, int);
int find(int);
bool same(int, int);
int kruskal() {
sort(es, es + E, comp);
init();
int res = 0;
for(int i = 0; i < E; i++) {
edge e = es[i];
if(!same(e.u, e.v)) {
unite(e.u, e.v);
res += e.cost;
}
}
return res;
}
#define MAX_N MAX_V
int par[MAX_N];
int depth[MAX_N];
void init(int n) {
for(int i = 0; i < n; i++) {
par[i] = i;
depth[i] = 0;
}
}
int find(int x) {
if(par[x] == x) {
return x;
} else {
return par[x] = find(par[x]);
}
}
void unite(int x, int y) {
x = find(x);
y = find(y);
if(x == y) return;
if(depth[x] < depth[y]) {
par[x] = y;
} else {
par[y] = x;
if(depth[x] == depth[y]) depth[x]++;
}
}
bool same(int x, int y) {
return find(x) == find(y);
}