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Smallest positive missing number

Tisha Agarwal on January 30, 2022

Find the smallest positive missing number in the given array. Example: [0, -10, 1, 3, -20], Ans = 2 Constrains: 1<=N<=10^6 -10^6<=Ai<=1...
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Alex Lohr • • Edited

In JS, the solution would be filtering negative numbers and comparing to the index:

const smallestMissingPositiveNumber =
  (array) => array
    .filter(num => num >= 0)
    .find((num, idx) => num !== idx) - 1
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Obviously, if the positive numbers don't start at zero, we need to find out the starting number and add that as difference.

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Alex Lohr •

Since filter already creates a new array, there's no need to destructure it.

The only "real world application" I can think of is usually job interviews.