A simple sorting algorithm which moves elements one at a time into the correct position, moving higher ranked elements up as necessary. It repeats until no input elements remain.
Which Big O?
O ( 1 ) = constant time (process time same regardless of array size)
O ( log n ) = log arithmetic (needs to be sorted)
O ( n ) = linear (i.e. twitter followers, increasing size takes longer)
O ( n log n ) = semi linear
O (n2) = quadratic (for loops)
O ( nk ) = polynomial
O ( Kn ) = Exponential time
O ( n! ) = factorial time
sudo code for algorithm
for i = 1 to n - 1 //loops over the index of the entry to be inserted
j = i
while j > 0 and A[j] < A[j - 1] // while loop performs the insertion
swap(A[j], A[j - 1}) //swaps the element before as long as it is less
j = j - 1
The Code
How it works...
When to use it
Good
simplicity and efficiency
takes advantage of presorting
efficient for quite small data sets
more efficient in practice than most other simple quadratic algorithm such as selection sort or bubble sort
Bad
less efficient on large lists than more advanced algorithms such as quick sort, heap sort or merge sort
