Update array.md

Author: Swastyy

en/Data Structures/Arrays/array.md

@@ -1,6 +1,7 @@
 # Arrays
 
-Arrays are the most basic data structures used in programming. They contain a group of a fixed number of elements that occupy the same space in memory. I.e., the memory occupied is known at compile time. The values of elements in an array can be retrieved very quickly in `O(1)` time.
+Arrays are the most basic data structures used in programming. There are two types of arrays - static arrays and dynamic arrays. Static arrays contain a group of a fixed number of elements that occupy the same space in memory. I.e., the memory occupied is known at compile time whereas in the case of dynamic arrays the size is not fixed.
+The values of elements in an array can be retrieved very quickly in `O(1)` time.
 All arrays consist of contiguous memory locations. We can access the elements with their index. The lowest address corresponds to the first element, and the highest address to the last element.
 
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