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Coding/Arrays and strings

Add two large numbers stored as digit lists

Write codeEasy10 minMicrosoft and Amazon style

Your task

A settlement service keeps very large amounts as lists of decimal digits, most significant digit first, because an amount can run to 100,000 digits.

Write add_two_numbers(a, b) that returns the sum of the two amounts as a list of digits in the same form.

Input and output:

  • a, b: two non-negative integers, each a list of 1 to 100,000 digits from 0 to 9, most significant digit first.
  • Returns the sum as a list of digits from 0 to 9, most significant digit first.

Rules:

  • The two lists can have different lengths.
  • An input never starts with 0, except the number zero itself, which is [0].
  • The result never starts with 0, except a sum of zero, which is [0].

Examples

add_two_numbers(a: list[int], b: list[int]) -> list[int]
Example 1
Inputadd_two_numbers([7, 2, 4, 3], [5, 6, 4])
Output[7, 8, 0, 7]
Example 2
Inputadd_two_numbers([4, 6], [5, 8])
Output[1, 0, 4]