Run-Length Decode a String

Medium ⏱ 12 min 60% acceptance ★★★★★ 4.5

Write run_length_decode(s) that reverses run-length encoding: given a string of character + count pairs (counts may be more than one digit, e.g. "a12b1"), expand it back into the original repeated-character string.

Examples

Example 1

Input

s = 'a3b2c1'

Output

'aaabbc'

Explanation

'a' x3, 'b' x2, 'c' x1, concatenated.

Example 2

Input

s = 'a12b1'

Output

'aaaaaaaaaaaab'

Explanation

The count can span multiple digits (12), so digit-scanning must not stop after one character.

Constraints

s is a valid run-length-encoded string: one letter followed by one or more digits, repeated.

Topics

StringsString Compression

Companies

AmazonFlipkart

Hints

Hint 1

Walk through s: read one character, then keep consuming digits with `str.isdigit()` until you hit the next letter.

Hint 2

`int(...)` the accumulated digit string to get the repeat count.

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