An undirected graph:
0 <--> 1 4 
1 <--> 0 4 
2 <--> 5 
3 <--> 
4 <--> 1 0 
5 <--> 2 

representative[0] = 1
representative[1] = 1
representative[2] = 5
representative[3] = 3
representative[4] = 1
representative[5] = 5

component 0 contains: 4 1 0 
component 1 contains: 3 
component 2 contains: 5 2 
