Consider the following two$-$pointer style Python program which finds whether a given string

$s$ is a palindrome or not:

def check$\_$if$\_$palindrome$($s$)$:

left $=0$

right $=$ len$($s$)-1$

while left $$ right:

if s$[$left$]!=$ s$[$right$]$:

return False

left $\}+=$

right $==1$

return True

Prove correctness and termination. Clearly state the loop variant and the loop invariant,

and use induction properly.