merge_sort practice

binary_search.py

@@ -0,0 +1,24 @@
+def binary_search(arr, target):
+    left = 0
+    right = len(arr) - 1
+    mid = left + (right - left) // 2
+    print("left: ", left)
+    print("right: ", right)
+    print("mid: ", mid)
+    while left <= right:
+        if arr[mid] ==  target:
+            return mid
+        elif arr[mid] < target:
+            left = mid + 1
+        else:
+            right = mid - 1
+        mid = left + (right - left) // 2
+        # print("left: ", left)
+        # print("right: ", right)
+        # print("mid: ", mid)
+    return -1
+
+arr = [1,2,3,4,5,6,7,8,9,10,11,12,13,14]
+target = 4
+mid = binary_search(arr, target)
+print("target index: ", mid)

merge_sort.py

@@ -0,0 +1,32 @@
+def merge_sort(A):
+    if len(A) > 1:
+        mid = len(A) // 2
+        B = A[:mid]
+        C = A[mid:]
+        merge_sort(B)
+        merge_sort(C)
+
+        i = j = k = 0
+
+        while i < len(B) and j < len(C):
+            if B[i] < C[j]:
+                A[k] = B[i]
+                i += 1
+            else:
+                A[k] = C[j]
+                j +=1
+            k += 1
+
+        while i < len(B):
+            A[k] = B[i]
+            i += 1
+            k += 1
+
+        while j < len(C):
+            A[k] = C[j]
+            j += 1
+            k += 1
+
+A = [9,8,7,6,5,4,3,2,1]
+merge_sort(A)
+print(A)