Kata

Given an array of integers of any length, return an array that has 1 added to the value represented by the array.

the array can’t be empty
only non-negative, single digit integers are allowed
Return nil (or your language’s equivalent) for invalid inputs.

Examples
For example the array [2, 3, 9] equals 239, adding one would return the array [2, 4, 0].

[4, 3, 2, 5] would return [4, 3, 2, 6]

# Other Answer

bignumber 라이브러리 사용

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const BigNumber = require('bignumber.js');

const upArray = arr =>
  arr.length === 0 || arr.filter(x => x < 0 || x > 9).length > 0
    ? null
    : (new BigNumber(arr.join('')).plus(1))
        .toPrecision()
        .split('')
        .map(Number);

# thoughts

  • js 에서 일정 범위를 넘으면 숫자가 그대로 표현되지 않는다.
  • 쉬운 문제였지만 오래걸렸던 것은 이 숫자를 어떻게 풀어내느냐가 관건

references