initial commit

src/iterative_sorting/iterative_sorting.py

@@ -5,25 +5,55 @@ def selection_sort( arr ):
         cur_index = i
         smallest_index = cur_index
         # TO-DO: find next smallest element
-        # (hint, can do in 3 loc) 
-
+        # (hint, can do in 3 loc)
 
+    # b. Iterate to the left until you find the correct index in the "sorted" part of the array at which this element should be inserted  
+    # - Shift items over to the right as you iterate
 
+        for j in range(cur_index, len(arr)):
+            if arr[j] < arr[smallest_index]:
+                smallest_index = j
 
+    # c. When the correct index is found, copy temp into this position
         # TO-DO: 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 ):
 
+# make flag to show if swap has occured
+    swaps_occured = True
+    # Run until no swaps
+    while swaps_occured:
+        swaps_occured = False
+
+    #for each element in the array...
+        for i in range(len(arr) - 1):
+
+        # check neighbor to the right
+            if arr[i] > arr[i+1]:
+
+        # if neighbor is smaller, swap and make flag true
+                arr[i],  arr[i+1] =  arr[i+1], arr[i]
+                swaps_occured = True
+
     return arr
 
 
+
+
+
+
+
 # STRETCH: implement the Count Sort function below
 def count_sort( arr, maximum=-1 ):
 

src/recursive_sorting/recursive_sorting.py

@@ -1,17 +1,57 @@
 # TO-DO: complete the helpe function below to merge 2 sorted arrays
+# a = [1,3,5] 
+# b = [2,4,6]
+# merged_arr= [1, 2, 0, 0, 0, 0]
 def merge( arrA, arrB ):
     elements = len( arrA ) + len( arrB )
     merged_arr = [0] * elements
     # TO-DO
+
+    #initialize pointers to first element of both arrays
+    a = 0 # these are indexes
+    b = 0
+    #compare arr[0] of arrA and arrB
+    for i in range(elements):
+        if a >= len(arrA):
+            print(i)
+            merged_arr[i] = arrB[b]
+            b += 1
+        elif b >= len(arrB):
+            merged_arr[i] = arrA[a]
+            a += 1
+        elif arrA[a] < arrB[b]:
+            merged_arr[i] = arrA[a]
+            a += 1
+        else:
+            merged_arr[i] = arrB[b]
+            b += 1
+
+
+    #copy the smallest to merged_arr
 
     return merged_arr
 
+
+
 
 # TO-DO: implement the Merge Sort function below USING RECURSION
 def merge_sort( arr ):
     # TO-DO
+    # base case - if len(arr) == 1, return arr
+    if len(arr) <= 1:
+        return arr
 
-    return arr
+    #split arr in half
+    left = arr[:len(arr) // 2]
+    right = arr[len(arr) // 2:] #trouble understanding this slice
+
+    #sort each half
+    left = merge_sort(left)
+    right = merge_sort(right)
+
+    #merge them back together
+    #return arr
+    return merge(left, right)
 
 
 # STRETCH: implement an in-place merge sort algorithm