2 files changed, 58 insertions, 2 deletions
diff --git a/src/03/04/README.md b/src/03/04/README.md
index 0a95052..fb94660 100644
--- a/src/03/04/README.md
+++ b/src/03/04/README.md
@@ -3,6 +3,54 @@ following algorithms, and illustrate the details of the execution of the
 algorithms:
 
 a. merge-sort algorithm.
+
+```plaintext
+[3,1,4,1,5,9,2,6,5,3,5,]
+[3,1,4,1,5,9,]
+[3,1,4,]
+[3,1,]
+[3,]
+[3,1,]
+[1,3,4,]
+[1,3,4,1,5,9,]
+[1,3,4,1,5,]
+[1,3,4,1,]
+[1,3,4,1,5,]
+[1,3,4,1,5,9,]
+[1,1,3,4,5,9,2,6,5,3,5,]
+[1,1,3,4,5,9,2,6,5,]
+[1,1,3,4,5,9,2,6,]
+[1,1,3,4,5,9,2,]
+[1,1,3,4,5,9,2,6,]
+[1,1,3,4,5,9,2,6,5,]
+[1,1,3,4,5,9,2,5,6,3,5,]
+[1,1,3,4,5,9,2,5,6,3,]
+[1,1,3,4,5,9,2,5,6,3,5,]
+```
+
 b. quick-sort algorithm.
-  * Choose a partitioning strategy you like to pick a pivot element from the sequence.
-  * Analyze how different portioning strategies may impact on the performance of the sorting algorithm.
+* Choose a partitioning strategy you like to pick a pivot element from the sequence.
+* Analyze how different portioning strategies may impact on the performance of the sorting algorithm.
+
+For choosing a pivot I chose to use the value in the last element of the sequence.
+Alternative, strategies include choosing a random pivot in each sub-sequence.
+
+Using the last item in the sub-sequence as the pivot:
+
+```plaintext
+[3,1,4,1,5,9,2,6,5,3,]
+[3,1,4,1,2,]
+[1,1,]
+[1,]
+[]
+[1,]
+[1,1,]
+[1,1,2,3,4,]
+[1,1,2,]
+[1,1,2,3,3,]
+[1,1,2,3,3,4,5,6,5,9,]
+[1,1,2,3,3,4,]
+[1,1,2,3,3,4,5,5,5,9,]
+[1,1,2,3,3,4,5,5,]
+[1,1,2,3,3,4,5,5,5,6,]
+```
diff --git a/src/03/sort.c b/src/03/sort.c
index d67bfff..d46a8d6 100644
--- a/src/03/sort.c
+++ b/src/03/sort.c
@@ -1,6 +1,14 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+static void dump(int *items, int n)
+{
+  printf("[");
+  for (int i = 0; i < n; ++i)
+    printf("%d,", items[i]);
+  printf("]\n");
+}
+
 static void _merge(int *items, int min, int mid, int max) {
   int length = (max-min) + 1;
   int tmp[length];