Colin toft

src/iterative_sorting/iterative_sorting.py

@@ -1,30 +1,49 @@
 # TO-DO: Complete the selection_sort() function below 
 def selection_sort( arr ):
-    # loop through n-1 elements
-    for i in range(0, len(arr) - 1):
-        cur_index = i
-        smallest_index = cur_index
-        # TO-DO: find next smallest element
-        # (hint, can do in 3 loc) 
-
-
-
-
-        # TO-DO: swap
-
-
-
-
-    return arr
+#     # loop through n-1 elements
+#     # len(arr) => 5
+#     # out of bounds
+#     # len(arr) - 1
+#     # 4 -> 3 
+     for i in range(0, len(arr) - 1): 
+         cur_index = i
+         smallest_index = cur_index
+#         # TO-DO: find next smallest element
+#         # (hint, can do in 3 loc) 
+#         # iterate over a range
+         for j in range(cur_index, len(arr)):
+             if arr[j] < arr[smallest_index]:
+                 smallest_index = j
+
+
+#         # swap
+         arr[smallest_index], arr[cur_index] = arr[cur_index], arr[smallest_index]
+
+     return arr
 
 
 # TO-DO:  implement the Bubble Sort function below
 def bubble_sort( arr ):
+    n = len(arr)
+
+    for i in range(n):
+        for j in range(n-i-1):
+            if arr[j] > arr[j+1] :
+                arr[j], arr[j+1] = arr[j+1], arr[j] ## keep swapping the order and change the position ( 5 1 4 2 8 ) –> ( 1 5 4 2 8 ) an so on 
 
     return arr
 
 
 # STRETCH: implement the Count Sort function below
 def count_sort( arr, maximum=-1 ):
+    m = maximum = 0
+    count = [0] * m               
+    for a in arr:
+        count[a] += 1             
+    i = 0
+    for a in range(m):           
+        for c in range(count[a]): 
+            arr[i] = a
+            i += 1
 
     return arr

src/iterative_sorting/test_iterative.py

@@ -26,16 +26,16 @@ def test_bubble_sort(self):
         self.assertEqual(bubble_sort(arr4), sorted(arr4))
 
     # Uncomment this test to test your count_sort implementation
-    # def test_counting_sort(self):
-    #     arr1 = [1, 5, 8, 4, 2, 9, 6, 0, 3, 7]
-    #     arr2 = []
-    #     arr3 = [1, 5, -2, 4, 3]
-    #     arr4 = random.sample(range(200), 50)
-
-    #     self.assertEqual(count_sort(arr1), [0,1,2,3,4,5,6,7,8,9])
-    #     self.assertEqual(count_sort(arr2), [])
-    #     self.assertEqual(count_sort(arr3), "Error, negative numbers not allowed in Count Sort")
-    #     self.assertEqual(count_sort(arr4), sorted(arr4))
+    def test_counting_sort(self):
+         arr1 = [1, 5, 8, 4, 2, 9, 6, 0, 3, 7]
+         arr2 = []
+         arr3 = [1, 5, -2, 4, 3]
+         arr4 = random.sample(range(200), 50)
+
+         self.assertEqual(count_sort(arr1), [0,1,2,3,4,5,6,7,8,9])
+         self.assertEqual(count_sort(arr2), [])
+         self.assertEqual(count_sort(arr3), "Error, negative numbers not allowed in Count Sort")
+         self.assertEqual(count_sort(arr4), sorted(arr4))
 
 
 if __name__ == '__main__':

src/recursive_sorting/recursive_sorting.py

@@ -3,14 +3,38 @@ def merge( arrA, arrB ):
     elements = len( arrA ) + len( arrB )
     merged_arr = [0] * elements
     # TO-DO
-
+    L = 0
+    R = 0
+    for i in range(0, elements):
+        if L >= len(arrA):
+            merged_arr[i] = arrB[R]
+            R += 1
+        elif R >= len(arrB):
+            merged_arr[i] = arrA[L]
+            L += 1
+        elif arrA[L] < arrB[R]:
+            merged_arr[i] = arrA[L]
+            L += 1
+        else:
+            merged_arr[i] = arrB[R]
+            R += 1
     return merged_arr
 
 
 # TO-DO: implement the Merge Sort function below USING RECURSION
 def merge_sort( arr ):
-    # TO-DO
+
+    if(len(arr) <= 1):
+        return arr
+    else:
+        half = len(arr) // 2
+        arr1 = arr[half:]
+        arr2 = arr[:half]
+
+        ms_1 = merge_sort(arr1)
+        ms_2 = merge_sort(arr2)
 
+        return merge(ms_1, ms_2)
     return arr
 
 

src/searching/searching.py

@@ -3,6 +3,10 @@ def linear_search(arr, target):
 
   # TO-DO: add missing code
 
+   for value in arr:
+     if value == target:
+       return 1
+
    return -1   # not found
 
 

src/searching/test_searching.py

@@ -1,4 +1,4 @@
-import unittest
+import unittest 
 from searching import *