. 2023 Apr 20;9:e1339. doi: 10.7717/peerj-cs.1339

Algorithm 1: An algorithm to compute a parsimonious tree from a minimum spanning tree.

Data: T₁ a minimum spanning tree, with edge set

E (T_{1})

Result: T₂ a labeled tree, with edge set

E (T_{2})

E (T_{2}) \leftarrow \emptyset

;

while

| E (T_{1}) | \neq 0

L \leftarrow l e a v e s (T_{1})

;

P \leftarrow p r e d e c e s s o r s (L)

;

P \neq L t h e n

E (T_{2}) \leftarrow E (T_{2}) + {(u, v, d (u, v)), u \in L, v \in P}

;

E (T_{2}) \leftarrow E (T_{2}) + {(v, v, 0), v \in P}

;

E (T_{1}) \leftarrow E (T_{1}) - {(u, v, d (u, v)), u \in L, v \in P}

;

else

E (T_{2}) \leftarrow E (T_{2}) + {(L [0], L [1], d (L [0], L [1]))}

;

E (T_{2}) \leftarrow E (T_{2}) + {(L [1], L [1], 0)}

;

E (T_{1}) \leftarrow E (T_{1}) - {(L [0], L [1], d (L [0], L [1])),}

;

end