edges
    0    1    2    3    4

0   1    1    0    1    1
1   0    0    0    0    0
2   0    1    0    1    1
3   0    0    0    0    1
4   0    1    0    0    0

reachability
    0    1    2    3    4

0   1    1    0    1    1
1   0    0    0    0    0
2   0    1    0    1    1
3   0    1    0    0    1
4   0    1    0    0    0