Program in insertion sort

If the first element is greater than key , then key is placed in front of the first element. If the first element is greater than key, then key is placed in front of the first element. Now, the first two elements are sorted. Take the third element and compare it with the elements on the left of it.

Placed it just behind the element smaller than it. If there is no element smaller than it, then place it at the beginning of the array. Place 1 at the beginning Similarly, place every unsorted element at its correct position. Previous Tutorial:. Next Tutorial:. Share on:. The only difference is, this program uses a user-defined function insertionSort to sort an array entered by user. Here is its sample run with user input, 10 as size, and 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 as elements for the array:.

All Rights Reserved. Return 1. Step2 - Pick the next element, and store it separately in a key. Step3 - Now, compare the key with all elements in the sorted array.

Step 4 - If the element in the sorted array is smaller than the current element, then move to the next element. Else, shift greater elements in the array towards the right. To understand the working of the insertion sort algorithm, let's take an unsorted array. It will be easier to understand the insertion sort via an example.

Here, 31 is greater than That means both elements are already in ascending order. So, for now, 12 is stored in a sorted sub-array. Here, 25 is smaller than So, 31 is not at correct position. Now, swap 31 with Along with swapping, insertion sort will also check it with all elements in the sorted array.

For now, the sorted array has only one element, i. So, 25 is greater than Hence, the sorted array remains sorted after swapping. Now, two elements in the sorted array are 12 and Move forward to the next elements that are 31 and 8. Now, the sorted array has three items that are 8, 12 and Move to the next items that are 31 and Now, let's see the time complexity of insertion sort in best case, average case, and in worst case. We will also see the space complexity of insertion sort.

This article was not only limited to the algorithm. The array is virtually split into a sorted and an unsorted part.

Values from the unsorted part are picked and placed at the correct position in the sorted part. Algorithm To sort an array of size n in ascending order: 1: Iterate from arr[1] to arr[n] over the array. Move the greater elements one position up to make space for the swapped element. Skip to content.

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