diff --git a/primitiveCollections/src/main/java/org/lucares/collections/IntList.java b/primitiveCollections/src/main/java/org/lucares/collections/IntList.java
index adffe47..33f8d22 100644
--- a/primitiveCollections/src/main/java/org/lucares/collections/IntList.java
+++ b/primitiveCollections/src/main/java/org/lucares/collections/IntList.java
@@ -342,6 +342,11 @@ public final class IntList implements Serializable, Cloneable {
 	 * <p>
 	 * This method does not release any memory. Call {@link #trim()} to free unused
 	 * memory.
+	 * <p>
+	 * If {@code retain} is sorted, then the algorithm has a complexity of
+	 * O(n*log(m)), where n is the length of {@code this} and m the length of
+	 * {@code retain}. If {@code retain} is not sorted, then the complexity is
+	 * O(n*m).
 	 *
 	 * @param remove
 	 *            the elements to remove
@@ -350,19 +355,7 @@ public final class IntList implements Serializable, Cloneable {
 	 * @see #trim()
 	 */
 	public void removeAll(final IntList remove) {
-
-		int insertPosition = 0;
-		for (int i = 0; i < size; i++) {
-			final int current = data[i];
-			if (remove.indexOf(current) < 0) {
-				// keep current element
-				data[insertPosition] = current;
-				insertPosition++;
-			}
-		}
-		size = insertPosition;
-
-		sorted = size() <= 1 ? true : sorted; // lists of size 1 or smaller are always sorted
+		removeIf((val, index) -> remove.indexOf(val) >= 0);
 	}
 
 	/**
@@ -403,8 +396,10 @@ public final class IntList implements Serializable, Cloneable {
 	 * For a method that computes the intersection of two lists and also removes
 	 * duplicate values, see {@link #intersection(IntList, IntList)}.
 	 * <p>
-	 * The algorithm has a complexity of O(n*log(m)), where n is the length of
-	 * {@code this} and m the length of {@code retain}.
+	 * If {@code retain} is sorted, then the algorithm has a complexity of
+	 * O(n*log(m)), where n is the length of {@code this} and m the length of
+	 * {@code retain}. If {@code retain} is not sorted, then the complexity is
+	 * O(n*m).
 	 *
 	 * @param retain
 	 *            the elements to retain
@@ -414,17 +409,7 @@ public final class IntList implements Serializable, Cloneable {
 	 * @see #intersection(IntList, IntList)
 	 */
 	public void retainAll(final IntList retain) {
-
-		int insertPosition = 0;
-		for (int i = 0; i < size; i++) {
-			final int current = data[i];
-			if (retain.indexOf(current) >= 0) {
-				// keep current element
-				data[insertPosition] = current;
-				insertPosition++;
-			}
-		}
-		size = insertPosition;
+		removeIf((val, index) -> retain.indexOf(val) < 0);
 	}
 
 	/**