Pattern Finding from a Tree

Given an undirected tree, $T$, each vertex in $T$ is represented by a lowercase letter from English alphabet. The tree, $T$ is represented by adjacency lists. Let $P$ be a pattern string represented by an array of lowercase letters from English alphabet. For example, $T$ has five vertices $a$, $b$, $c$, $e$, $f$, out of which $a$ is the root. The adjacency list representation of $T$ is $-$ $a$ ->