# DCP29 - AAAABBBCCD

Sep 28th, 2020
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1. '''
2. This problem was asked by Amazon.
3. Run-length encoding is a fast and simple method of encoding strings. The basic idea is to represent repeated successive characters as a single count
4. and character. For example, the string "AAAABBBCCDAA" would be encoded as "4A3B2C1D2A".
5. Implement run-length encoding and decoding. You can assume the string to be encoded have no digits and consists solely of alphabetic characters.
6. You can assume the string to be decoded is valid.
7. '''
8. from timeit import default_timer as timer
9.
10. def solve(message):
11.     n = len(message)
12.     letters = list()
13.     letters.append(message[0])
14.     counters = list()
15.     counters.append(1)
16.     for i in range(1, n):
17.         if message[i] == letters[len(letters)-1]:
18.             counters[len(counters)-1] += 1
19.         else:
20.             letters.append(message[i])
21.             counters.append(1)
22.
23.     # Now, I have to create the returned string based on the 2 lists
24.     result = ""
25.     if len(letters) != len(counters):
26.         print("Error using function 'solve'.")
27.         return -1000
28.     for i in range(len(letters)):
29.         result += (str(counters[i]) + letters[i])
30.     return result
31.
32. def prettyPrint(message):
33.     start = timer()
34.     result = solve(message)
35.     end = timer()
36.     elapsed = 10**6 * (end - start)
37.     print(message + " ----> " + str(result) + " (" + str(round(elapsed, 2)) + " μs)")
38.
39.
40. # MAIN FUNCTION
41. print()
42. messages = ["AAAAAAAAAKK", "AAAABBBCCDAA", "AAABBBaaabbbAAA", "asdfQWE"]
43. for message in messages:
44.     prettyPrint(message)
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