Global Alignment of Pairwise Protein Interaction Networks for Maximal Common Conserved Patterns

Pseudocode 1

Pseudocode of the connected-component algorithm.

(1) Input: Graph G = (V, E), Start node v0

(2) index = 0     // DFS node number counter

(3)  S = empty     // An empty stack of nodes

(4)   tarjan (v0)   // Start a DFS at the start node

(5)   procedure tarjan (v)

(6)  v.index = index  // Set the depth index for v

(7)  v.lowlink = index

(8)  index = index + 1

(9)  S.push (v)    // Push 𝑣 on the stack

(10)  For all (v, 𝑣^′) in E do // Consider successors of v

(11)   if (𝑣^′.index is undefined) // Was successor 𝑣^′ visited?

(12)   tarjan (𝑣^′)   // Recurse

(13)   𝑣.lowlink = min (𝑣.lowlink, 𝑣^′.lowlink)

(14)   elseif (𝑣^′ in S)     // Is 𝑣^′ on the stack?

(15)   𝑣.lowlink = min (𝑣.lowlink, 𝑣^′.index)

(16)  if (𝑣.lowlink == 𝑣.index) // Is 𝑣 the root of an SCC?

(17)   print “SCC:”

(18)   repeat

(19)   𝑣^′ = 𝑆.pop

(20)   print 𝑣^′

(21)   until (𝑣^′ == v)