Errata: Data Structures and Algorithms Book!

programming
5

Insertion Sort - Fixed undeclared j variable
The following code declares the j variable correctly to avoid any out-of-scope errors:

function insertionSort(input) {
  // Variable to store the current element being compared
  let activeNumber;

  // Loop through the array starting from the second element (index 1)
  for (let i = 1; i < input.length; i++) {
    // Store the current element in the activeNumber variable
    activeNumber = input[i];

    let j;
    
    // Inner loop to compare the activeNumber with the elements before it
    for (j = i - 1; j >= 0; j--) {
      if (input[j] > activeNumber) {
        // Move the greater element one position ahead to make space 
        // for the activeNumber
        input[j + 1] = input[j];
      } else {
        // If we find an element that is smaller than or 
        // equal to the activeNumber, exit the inner loop
        break;
      }
    }
    // Place the activeNumber in its correct sorted position
    input[j + 1] = activeNumber;
  }
}

let myinput = [24, 10, 17, 9, 5, 9, 1, 23, 300];
insertionSort(myinput);

console.log(myinput);

Thanks to @transbot for finding this one as well! :slight_smile: