How does the insertion sort algorithm sort elements?

Insertion sort algorithm sorts elements by comparing each element with its predecessor and inserting it at the correct position.

The insertion sort algorithm is a simple sorting algorithm that works similarly to the way you might sort playing cards in your hand. The algorithm begins at the second element and checks if it is smaller than the first element. If it is, these elements are swapped. The algorithm then moves on to the third element and checks if it is smaller than the previous elements. If it is, it is moved to its correct position among the previous elements. This process continues until all elements in the list have been sorted.

The algorithm works by dividing the list into a sorted and an unsorted region. The sorted region starts with the first element and the unsorted region starts with the second element. The algorithm repeatedly picks the first element from the unsorted region and moves it to the correct position in the sorted region. This is done by shifting the larger elements in the sorted region to make space for the new element.

The insertion sort algorithm is efficient for small lists or for lists that are already partially sorted. However, for larger lists, the algorithm can be quite slow. This is because it requires comparing each element with all the previous elements and potentially moving a large number of elements to make space for a new element.

In terms of complexity, the best case scenario for insertion sort is when the list is already sorted. In this case, the algorithm only needs to go through the list once, resulting in a time complexity of O(n). The worst case scenario is when the list is sorted in reverse order. In this case, each insertion requires shifting all the sorted elements, resulting in a time complexity of O(n^2).

In conclusion, the insertion sort algorithm is a simple and intuitive sorting algorithm that works well for small or partially sorted lists. However, it is not the most efficient algorithm for larger lists or lists that are sorted in reverse order.