-
Notifications
You must be signed in to change notification settings - Fork 0
/
DSU_Cycle_Detection.cpp
61 lines (60 loc) · 1.25 KB
/
DSU_Cycle_Detection.cpp
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
#include<iostream>
#include<list>
using namespace std;
class Graph{
int V;
list<pair<int,int>> L;
public:
Graph(int V)
{
this->V=V;
}
void AddEdge(int u,int v)
{
L.push_back(make_pair(u,v));
}
int find_set(int i, int parent[])
{
if(parent[i]==-1)
return i;
return find_set(parent[i], parent);
}
void union_set(int x,int y,int parent[])
{
int s1=find_set(x,parent);
int s2=find_set(y, parent);
if(s1!=s2)
parent[s2]=s1;
}
bool contains_cycle()
{
int *parent=new int[V];
for(int i=0; i<V; i++)
parent[i]=-1;
for(auto edge:L)
{
int i=edge.first;
int j=edge.second;
int s1=find_set(i, parent);
int s2=find_set(j,parent);
if(s1!=s2)
union_set(s1,s2,parent);
else
return true;
}
delete [] parent;
return false;
}
};
int main()
{
Graph G(4);
G.AddEdge(0, 1);
G.AddEdge(1, 2);
G.AddEdge(2, 3);
G.AddEdge(3, 0);
if(G.contains_cycle())
cout<<"Graph has a cycle"<<endl;
else
cout<<"Graph does not contain a cycle"<<endl;
}