Not a valid solution

coding_test.py

# codeinterview.io

# You are envolved in a development of a new binary serialization 
# protocol. Your first task is to implemnt `enumerateChars` 
#  function. The function builds dictionary where key is character found in 
#  the strings and value corresponding coordinates of that character (string index 
#  in the sequence, character index in the string)
#  
#  Arguments:
# strings: list of strings
  
# Returns: mapping of each character 
#          found ifn `strings` to it's coordiantes `(x, y)`, 
#          where `x the index of string the character is part of and
#          `y` the index of character inside the string.
#          Indexing starts from 1. 
  
# Example:
#   For the `['zx', 'xy', 'ycaa', 'aca', 'c']` the result would be:
#   {[(3,3),(3,4),(4,1),(4,3)]
#    'a' : ,
#    'c' : [(3,2),(4,2),(5,1)],
#    'x' : [(1,2),(2,1))],
#    'y' : [(2,2),(3,1))],
#    'z' : [(1,1)]
#   }
#

from collections import OrderedDict

def task(strings: list) -> dict:

  characters_index = {}
  
  
  # O(n^2)
  for i, string in enumerate(strings):
    for j, character in enumerate(string):

      if character in characters_index.keys():
        characters_index[character].append((i+1, j+1))
      else:
        characters_index[character] = [(i+1, j+1)]

  # [[{'a': (1)}, {'b': (2)}], [{'b': (1)}, {'a': (2)}]]
  # O(n) + O(n)
  map1 = map(
    lambda tup:
      {character: (tup[0], j) for (j, character) in enumerate(string)} , enumerate(strings))

  print(list(map1))  

  return characters_index

# input  
['ab', 'ba']

# 1st mapping



OrderedDict()

# print(task(['ab', 'ba']))

assert task(['ab', 'ba']) == {'a': [(1,1),(2,2)], 'b': [(1,2),(2,1)]}  
assert task(['aa', 'aaa']) == {'a': [(1,1),(1,2),(2,1),(2,2),(2,3)]}
assert task(["zx", "xy", "ycaa", "aca", "c"]) == {'a' : [(3,3),(3,4),(4,1),(4,3)], 'c' : [(3,2),(4,2),(5,1)], 'x' : [(1,2),(2,1)], 'y' : [(2,2),(3,1)], 'z' : [(1,1)]}