step         d/pi s  d/pi a  d/pi b  d/pi c  d/pi d  d/pi e
init            0/-   inf/-   inf/-   inf/-   inf/-   inf/-
1: s            0/-     4/s     1/s   inf/-   inf/-   inf/-
2: b            0/-     3/b     1/s     9/b    11/b   inf/-
3: a            0/-     3/b     1/s     8/a    11/b   inf/-
4: c            0/-     3/b     1/s     8/a    10/c    14/c
5: d            0/-     3/b     1/s     8/a    10/c    11/d
6: e            0/-     3/b     1/s     8/a    10/c    11/d

shortest paths from s:
  s  d =  0  path: s
  a  d =  3  path: s b a
  b  d =  1  path: s b
  c  d =  8  path: s b a c
  d  d = 10  path: s b a c d
  e  d = 11  path: s b a c d e
