資料結構與演算法(A)

(5 points) Many string-matching algorithms build a finite automata. Below is a partially-completed state transition function $\delta$ for a string $s$ of length 10 over the alphabet $\{A, B, C\}$ (columns are states $0\dots9$; a blank means unspecified). It is possible to reconstruct $s$ from the partial table. How many A's does the string $s$ have?