Playfair Prepare Pair

Problem

Apply the Playfair digraph preparation rules to two letters: convert J to I, and when the two letters are equal replace the second with X. Return the resulting two-character string.

Hint

Duplicate letters must be split before Playfair encryption.

Test cases

case 1

in: ["A","A"]

expected: "AX"

case 2

in: ["A","B"]

expected: "AB"

case 3

in: ["J","J"]

expected: "IX"

case 4

in: ["J","I"]

expected: "IX"

case 5

in: ["X","X"]

expected: "XX"

Starter codePython

def playfair_prepare_pair(a, b):
    # Your code here
    pass

5 test cases · run your code against them in the editor