practice programs

Author: purohitdheeraj

Native-Datatypes/reverse_string.py

@@ -0,0 +1,40 @@
+def len_str(string):
+    count = 0
+    for _ in string:
+        count += 1
+    return count
+
+def string_reversed(string):
+    len_string = len_str(string)-1
+    # print(len_string)
+    string_reversed = ''
+    dict_count = {}
+
+    while len_string >= 0:
+        string_reversed += string[len_string]
+        
+        if string[len_string] not in dict_count:
+            dict_count[string[len_string]] = 1
+        else:
+            dict_count[string[len_string]] += 1
+
+        len_string -= 1
+    return string_reversed # , dict_count
+
+# print(string_reversed('Hello World!'))
+
+def string_splitter(string):
+    tmp = ''
+    splitted_list = []
+    for c in string:
+        if c != ' ':
+            tmp += c
+        else:
+            splitted_list += tmp[::-1]
+            tmp = ''
+    if tmp:
+        splitted_list += tmp[::-1]
+        
+    return ''.join(splitted_list)
+
+print(string_splitter("Hello World")) 

binary_search_tree/binary_search_question_2.py

@@ -6,8 +6,6 @@
 
 "Sorted list" refers to a list where the elements are arranged in the increasing order e.g. [1, 3, 5, 7].'''
 
-
-
 def linear_rotated_search(list_of_num):
 
     count = 0
@@ -20,4 +18,44 @@ def linear_rotated_search(list_of_num):
             count += 1
     return 0
 
-print(linear_rotated_search([3,1,0]))
+def binary_search(lo, hi, condition):
+    while lo <= hi:
+        mid = (lo + hi)//2
+        result = condition(mid)
+        if result == 'found':
+            return mid
+        elif result == 'left':
+            hi = mid - 1
+        else:
+            lo = mid + 1
+    return 0
+
+
+def binary_rotated_array(list_of_num):
+    lo = 0
+    hi = len(list_of_num)-1
+    def condition(mid):
+        # position = 0
+        if mid > 0 and list_of_num[mid - 1] > list_of_num[mid]:
+            return 'found'
+        elif list_of_num[mid] < list_of_num[hi]:
+            return 'left'
+        else:
+            return 'right'
+    return binary_search(0, len(list_of_num)-1, condition) 
+
+def target_array_value(list_of_num, target):
+    pivot = binary_rotated_array(list_of_num)
+    def condition(mid):
+        if list_of_num[mid] == target:
+            return 'found'
+        if list_of_num[pivot] < list_of_num[len(list_of_num)-1]:
+            return 'right'
+        else:
+            return 'left'
+    return binary_search(0, len(list_of_num)-1, condition)
+    
+
+# print(linear_rotated_search([3,1,0]))
+# print(binary_rotated_array([5,1,2,3,4]))
+print(target_array_value([1,2,3,4,5,6,7,8,9], 4))

sorting/sort_program.py

@@ -0,0 +1,12 @@
+# problem 1- write aprogram to sort a list of numbers
+
+# input-output format: a list of unsorted numbers will be given to our function and function will give ouput sorted list. 
+
+# testcases
+# 1. randomly unsorted array
+# 2. empty list
+# 3. containing one element
+# 4. list containing repeating element
+# 5. list sorted in descending order.
+# 6. Long list
+# 7. Already Sorted