$2\mathrm{.}1-3$

Consider the searching problem:

Input: A sequence of $n$ numbers $A=($:$a_1,a_2,$dots,$a_n$:$)$ and a value $v.$

Output: An index i such that $v=A[i]$ or the special value NIL if $v$ does not

appear in $A.$

Write pseudocode for linear search, which scans through the sequence, looking

for $v.$ Using a loop invariant, prove that your algorithm is correct. Make sure that

your loop invariant fulfills the three necessary properties. Help me about this question please