Update 'README.md'

README.md

@@ -32,11 +32,17 @@ dependencies {
 
 # Examples
 
-```java
-import org.lucares.collections.IntList;
+## IntList / LongList
+An alternative to `int[]`/`long[]` that grows dynamically. The list supports a few features that are either not supported
+by arrays or that would be expensive to implement. The most unique feature is that the list knows if it is sorted.
 
-public class Example {
-	public static void main(final String[] args) {
+### isSorted()
+The lists keep track of whether they are sorted or not. This makes the call to `isSorted()` very cheap, because we only have to return the value of a field. The drawback is that some operations are much more expensive. This affects `shuffle()`,
+as well as `remove(int, int)`, `removeIf()`, `removeAll(IntList)` and 'retainAll()' if the list was not sorted before. 
+
+The fact that we know if a list is sorted allows us to use more efficient algorithms for `union(IntList, IntList)`, `intersection(IntList, IntList)`, `indexOf(int)`, `lastIndexOf()` and `uniq()`.
+
+```java
 final IntList list = IntList.of(1, 3, 5);
 System.out.println(list + " is sorted: " + list.isSorted());
 
@@ -45,8 +51,6 @@ public class Example {
 
 list.sort();
 System.out.println(list + " is sorted: " + list.isSorted());
-	}
-}
 
 ```
 Running this program gives the following output:
@@ -56,3 +60,9 @@ Running this program gives the following output:
 [1, 3, 7, 5] is sorted: false
 [1, 3, 5, 7] is sorted: true
 ```
+
+The fact that we know if a list is sorted allows us to use more efficient algorithms for `union(IntList, IntList)`, `intersection(IntList, IntList)`, `indexOf(int)`, `lastIndexOf()` and `uniq()`.
+
+
+
+