Task 1: "Majority Element

You are given an array of integers of size $N.

Write a script to find the majority element. If none found then print -1.
The majority element in a list is the element, if any, that appears more than
floor(size_of_list/2) TIMES.

Example 1

  Input: @A = (1, 2, 2, 3, 2, 4, 2)
  Output: 2, as 2 appears 4 times in the list - more than floor(7/2)==3 TIMES.

Example 2

  Input: @A = (1, 3, 1, 2, 4, 5)
  Output: -1 as none of the elements appears more than floor(6/2)==3 TIMES.
"

My notes: ok.  Very easy.


Task 2: "FNR Character

You are given a string $S.

Write a script to print the series of first non-repeating character (left -> right) for the given string. Print # if none found.

Example 1
  Input: $S = 'ababc'
  Output: 'abb#c'
  Pass 1: 'a', the FNR character is 'a'
  Pass 2: 'ab', the FNR character is 'b'
  Pass 3: 'aba', the FNR character is 'b'
  Pass 4: 'abab', no FNR found, hence '#'
  Pass 5: 'ababc' the FNR character is 'c'

Example 2
  Input: $S = 'xyzzyx'
  Output: 'xyzyx#'
  Pass 1: 'x', the FNR character is 'x'
  Pass 2: 'xy', the FNR character is 'y'
  Pass 3: 'xyz', the FNR character is 'z'
  Pass 4: 'xyzz', the FNR character is 'y'
  Pass 5: 'xyzzy', the FNR character is 'x'
  Pass 6: 'xyzzyx', no FNR found, hence '#'
"

My notes: why is the FNR of "ab" (in pass 2) 'b' rather than 'a'?  Last non-repeating
character would be more like it.  Basically: in each pass, take substr(1,len PASS) and then
remove each LAST char if it's duplicated earlier in the substring, otherwise that's the FNR.
If the string is empty, no FNR, print #.