Insertion Sort

Introduction

• Initialization:

  • The function insertionSort accepts an array arr as its argument.

  • const end = arr.length; stores the length of the array in the variable end.

• Element Comparison:

  • The outer loop starts at the second element (let start = 1) and iterates through the array until the end (start < end).

• Inner Loop:

  • For each element arr[start], it's stored in the variable curr.

  • The variable prev is initialized to start - 1, representing the index of the element before the current element.

• Shifting Elements:

  • The inner while loop compares curr with the elements before it (arr[prev]).

  • If arr[prev] is greater than curr, arr[prev] is moved one position ahead to make space for curr.

  • This continues until curr is greater than or equal to arr[prev] or prev becomes 1.

• Insertion:

  • Once the correct position is found, curr is inserted at that position (arr[prev + 1]).

• Returning the Result:

  • After all elements are processed, the sorted array arr is returned.

function insertionSort(arr) {
  const end = arr.length;

  for (let start = 1; start < end; start++) {
    let curr = arr[start];
    let prev = start - 1;

    while (prev >= 0 && arr[prev] > curr) {
      arr[prev + 1] = arr[prev];
      --prev;
    }

    arr[prev + 1] = curr;
  }

  return arr;
}

console.log(insertionSort([9, 5, 1, 4, 3]));