Help me in solving ST04 problem

My issue

not able to understand the logic behind the 15th line of the code

My code

#Update the '_' in the code below to solve this problem

t = int(input())
for i in range(t):
    A = input()
    B = input()
    i = 0
    n = len(A)
    #Flag is a very imporant tool in programming problems - you will come across various examples in later problems as well
    flag = 0
    while i<n:
        #Checking A from left to right and B from right to left
        if A[i]==B[n-i-1]:      
            i = i + 1
            #If specific character in A and B do not match, then they cannot be reverse of each other
            flag = 1
    if flag==1:

Learning course: Python for problem solving - 2
Problem Link: CodeChef: Practical coding for everyone

The logic here is that

  1. in while loop, we are checking from left to right in A string and from right to left in B string
  2. if we are getting same characters then we just move on
  3. but when we get different characters in A and B for a particular index, we just mark flag=1, which denotes that we got different characters.
  4. As, we got different characters, so there is no meaning of checking further. We just break the loop and come out.