Insertion Sort

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Insertion sort

Insertion-Sort(A)

1. for i = 2 to A.length
2. key = A[i]
3. j = i - 1
4. while j > 0 and A[j] > key
5. A[j + 1] = A[j]
6. j = j - 1
7. A[j + 1] = key

Insertion sort is an algorithm for Sorting Problem, arranging an un-ordered list to an ordered list. We assume the first element of the un-ordered list to be ordered such that:

• Sub-array: $[1, j-1]$ is sorted.
• Key: $[j]$ is the key we concern with.
• Sub-array: $[j+1, A.length]$ is concerned.

As the insertion sort operates, it is guaranteed that $[1, j-1]$ is sorted.