Write an algorithm for insertion sort. Analyze insertion sort algorithmfor best case and worst case.

Sure, here is an algorithm for insertion sort:

1. Start with the second element in the array.
2. Compare the second element with the first element. If the second element is smaller, swap them.
3. Move to the third element and compare it with the elements before it. Insert the third element in its correct position by shifting the larger elements to the right.
4. Repeat steps 2 and 3 for the remaining elements in the array.
5. The array is now sorted.

Now let's analyze the best case and worst case scenarios for insertion sort:

Best case scenario: In the best case scenario, the array is already sorted. In this case, the algorithm will only need to compare each element with its previous element and no swaps will be required. The time complexity for the best case scenario is O(n), where n is the number of elements in the array.

Worst case scenario: In the worst case scenario, the array is sorted in reverse order. In this case, each element will need to be compared with all the previous elements and multiple swaps will be required to insert each element in its correct position. The time complexity for the worst case scenario is O(n^2), where n is the number of elements in the array.

It is important to note that insertion sort is an efficient algorithm for small input sizes or partially sorted arrays, but it becomes less efficient as the input size increases.