Recursion PS pt 1 and 2 - A19 Gloria Wan

part-1.py

@@ -2,19 +2,64 @@
 # the required functions to build.
 # Please paste your solution underneath
 # the appropriate comment.
-
+##############################################
 # factorial
+##############################################
+def factorial(n):
+ if n == 0:
+ return 1
+ elif n < 0:
+ raise ValueError(f"{n} must be a positive integer")
+
+ return n*factorial(n-1)
 
 
-
+##############################################
 # reverse
+##############################################
+def reverse(text):
+ # checks to make sure the length of text is not 
+ if len(text) == 0:
+ return text
+ # adds the first to the end by using string operation
+ # text[0] is in a holding area until the recursion is completed
+ # reverse then slices the text string starting from the value 1
+ return reverse(text[1:]) + text[0]
+
 
-
-
+##############################################
 # bunny
+##############################################
+def bunny(count):
+ if count == 0:
+ return 0
+ return bunny(count-1)+2
 
 
-
+##############################################
 # is_nested_parens
+##############################################
+# function checks if the length of the string is even first
+def is_nested_parens(parens):
+ if len(parens)%2 != 0:
+ return False
+ else:
+ # function that will do recursion
+ return check_string(parens)
 
+# helper function that has a recursive that returns the string
+# without the first and last character
+def check_string(parens):
+ # condition to break recursion
+ if len(parens) == 0:
+ return True
+ # recursion act 
+ elif len(parens) > 0:
+ # first and last parenthesis should never be the same
+ if parens[0] == parens[-1]:
+ return False
+ # recursion that removes the first and last character
+ return check_string(parens[1:-1])
+ else:
+ return False
 

part-2.py

@@ -2,15 +2,59 @@
 # the required functions to build.
 # Please paste your solution underneath
 # the appropriate comment.
-
+##############################################
 # search
-
-
-
+##############################################
+def search(array,query):
+ # function will always check if the array is empty
+ if len(array) == 0:
+ return False
+ # the function will check if the first value against the value for query
+ elif array[0] == query:
+ return True
+ else:
+ # recursive function that removes the first value
+ return search(array[1:],query)
+
+##############################################
 # is_palindrome
-
-
-
+##############################################
+def is_palindrome(text):
+ # if the recursion empties the list it should break
+ if len(text) == 0:
+ return True
+ elif text[0] == text[-1]:
+ # recursive function that removes the first and last character
+ # it will keep getting called as long as the first and last character
+ # is the same
+ return is_palindrome(text[1:-1])
+ # if the first and last value does not equal each other
+ # if you have not reached the end of string
+ else:
+ return False
+
+##############################################
 # digit_match
-
+##############################################
+def digit_match(first_num, second_num):
+ num_match = 0
+ first_str = str(first_num)
+ second_str = str(second_num)
+
+ num_match += count_match(first_str, second_str, num_match)
+
+ return num_match
+
+# helper function that uses recursion to keep count
+def count_match (first_str, second_str,count):
+ # checks if we have reached the end of one integer
+ if len(first_str) == 0 or len(second_str) == 0:
+ return count
+ else:
+ # increase count if it matches
+ if first_str[-1] == second_str[-1]:
+ count += 1
+ # as long both strings are still populated it will remove the last
+ # integer for both and also pass the current count
+ return count_match(first_str[:-1], second_str[:-1], count)