Algorithm Where do I Belong

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🏁 Problem Explanation:

This can be a tricky problem to understand. You need to find where in the array a number should be inserted by order, and return the index where it should go.

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💬 Hint: 1

The first thing to do is sort the array from lower to bigger, just to make the code easier. This is where sort comes in, it needs a callback function so you have to create it.

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💬 Hint: 2

Once the array is sorted, then just check for the first number that is bigger and return the index.

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💬 Hint: 3

If there is no index for that number then you will have to deal with that case too.

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Spoiler Alert!


Solution ahead!

🔰 Basic Code Solution:

function getIndexToIns(arr, num) {
  arr.sort(function(a, b) {
    return a - b;

  for (var a = 0; a < arr.length; a++) {
    if (arr[a] >= num)
      return parseInt(a);

  return arr.length;

🚀 Run Code

Code Explanation:

  • First I sort the array using .sort(callbackFuntion) to sort it by lowest to highest, from left to right.
  • Then I use a for loop to compare the items in the array starting from the smallest one. When an item on the array is greater than the number we are comparing against, then we return the index as an integer.

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🌻 Intermediate Code Solution:

Using .findIndex()

function getIndexToIns(arr, num) {
  // sort and find right index
  var index = arr.sort((curr, next) => curr > next)
    .findIndex((currNum)=> num <= currNum);
  // Returns proper answer
  return index === -1 ? arr.length : index;

getIndexToIns([40, 60], 500);

🚀 Run Code

Code Explanation:

  • First sort the array in ascending order, this is currently done using array functions for minimal footprint.
  • Once the array it is sorted, we directly apply the .findIndex() where we are going to compare every element in the array until we find where num <= currNum meaning where the number we want to insert is less or equal to the current number number in the iteration.
  • Then we use ternary operations to check whether we got an index returned or -1. We only get -1 when the index was not found meaning when we get a false for all elements int he array, and for such case, it would mean that num should be inserted at the end of the list hence why we use arr.length.

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🏆 Credits:

If you found this page useful, you can give thanks by copying and pasting this on the main chat:

Thanks @Rafase282 for your help with Algorithm: Where do I belong


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