Merge pull request #21 from MatteoRaso/master

Added the insertion sorting algorithm

Author: cozek

algorithms/sorting/insertion_sort.m

@@ -0,0 +1,27 @@
+%A MATLAB/Octave implementation of the insertion sort algorithm.
+%The basic premise is that the program checks whether two neighbouring elements
+%in an array are in order and sorts them. It does length(array) number of
+% passes. For further details and pseudocode, refer to
+%https://en.wikipedia.org/wiki/Insertion_sort
+%Note that this function differs slightly from the pseudocode because of
+%how MATLAB/Octave arrays start at index 1.
+%Note: this function is for educational purposes only.
+%You will want to use the built-in sort function for actual coding,
+%as it is much more efficent.
+function y = insertion_sort(array)
+  i = 1;
+  %Assigning the length to a variable should make the program slightly faster.
+  len = length(array);
+  while i < len + 1
+    j = i;
+    while j > 1 && array(j - 1) > array(j)
+      %Swapping array(j - 1) and array(j)
+      temp = array(j - 1);
+      array(j - 1) = array(j);
+      array(j) = temp;
+      j = j - 1;
+    endwhile
+    i = i + 1;
+  endwhile
+  y = array;
+endfunction