This article is on the freeCodeCamp Basic Algorithm challenge “Where do I belong”.
The instructions are as thus:
“Return the lowest index at which a value (second argument) should be inserted into an array (first argument) once it has been sorted. The returned value should be a number.
For example, getIndexToIns([1,2,3,4], 1.5)should return 1 because it is greater than 1 (index 0), but less than 2 (index 1).
Likewise, getIndexToIns([20,3,5], 19) should return 2 because once the array has been sorted it will look like [3,5,20] and 19 is less than 20 (index 2) and greater than 5 (index 1).”
The test conditions are:
getIndexToIns([10, 20, 30, 40, 50], 35) should return 3.
getIndexToIns([10, 20, 30, 40, 50], 30) should return 2.
getIndexToIns([40, 60], 50)should return 1.
getIndexToIns([3, 10, 5], 3)should return 0.
getIndexToIns([5, 3, 20, 3], 5)should return 2.
getIndexToIns([2, 20, 10], 19)should return 2.
getIndexToIns([2, 5, 10], 15)should return 3.
Before we proceed, I‘ll advise the .sort() array method be read, as well as understand how a for loop and if statement works in JavaScript as these would be employed in solving the challenge.
See Code below:
Steps
Step 1:
Declare the function getIndexToIns and set parameters arr and num . Sort the argument of the parameter arr from lowest to highest as stated in the instruction using Array.sort() .
Step 2:
Create a for loop to loop through the index position i of the already sorted array arr , and an if statement where if the parameter num is less than or equal to any array item arr[i] looped through, return i which is the index position of the particular array item (actually the first array item) larger than num .
Step 3:
Exit the if statement and for loop , then return the length of the array arr . This is done to ensure that any num value larger than all the array arr item values will be given an assumed last index (or last position) in the array which is equal to arr.length .
Step 4:
Exit the function getIndexToIns and call the function with its likely arguments for example, getIndexToIns([10,5,20,40,38],35)
Voila! Now we know where everyone belongs!
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