Half way through checkpoint 3

lab.py

@@ -20,7 +20,11 @@ def scalar_fibonacci(n):
     >>> scalar_fibonacci(35)
     9227465
     """
-    return 0  # stub
+    if n <= 0:
+        return 0
+    if n == 1:
+        return 1
+    return scalar_fibonacci(n-1) + scalar_fibonacci(n-2)
 
 
 def vector_fibonacci(n):
@@ -41,9 +45,16 @@ def vector_fibonacci(n):
     >>> vector_fibonacci(35)
     (5702887, 9227465)
     >>> vector_fibonacci(350)
-    (3865462327928467072415604609040860366007401579690263197296200323999931849, 6254449428820551641549772190170184190608177514674331726439961915653414425)
+    (3865462327928467072415604609040860366007401579690263197296200323999931849L, 6254449428820551641549772190170184190608177514674331726439961915653414425L)
     """
-    return 0, 1  # stub
+    return vector_rec(n, 0, 1)
+
+def vector_rec(n, a, b):
+    if n > 1:
+        n -= 1
+        return vector_rec(n, b, a+b)
+    return a, b
+
 
 
 def maximal_repetition_free_prefix(sequence):
@@ -64,9 +75,12 @@ def maximal_repetition_free_prefix(sequence):
     [5, 4]
     >>> maximal_repetition_free_prefix([3, 2, 1, 2, 4])
     [3, 2, 1]
-
     """
-    return []  # stub
+    if len(sequence) <= 1:
+        return sequence
+    if len(sequence) > len(set(sequence)):
+        return maximal_repetition_free_prefix(sequence[0:len(sequence)-1])
+    return sequence
 
 
 def maximal_repetition_free_subsequence(sequence):
@@ -88,7 +102,11 @@ def maximal_repetition_free_subsequence(sequence):
     >>> maximal_repetition_free_subsequence([1, 2, 1, 2, 1, 2, 1])
     [2, 1]
     """
-    return []  # stub
+    if len(sequence) <= 1:
+        return sequence
+    if len(sequence) > len(set(sequence)):
+        return maximal_repetition_free_subsequence(sequence[1:len(sequence)])
+    return sequence
 
 
 def maximal_repetition_free_subsequence_version_2(sequence):