Unable to find error

#1

Problem : Sheldon Coope usnique character string heckerBlocks


tell me where am i doing wrong i am unable to score 100

#2

Hey, can you please explain your logic a bit?
I cannot understand your code properly

#3

Look at the program now i have commented the required field.

#4

It is not showing wrong answer ,i am getting run error in some test cases.