Useful examples of specific Python features

Author: DevCTx

practices/hard_interview.py

@@ -0,0 +1,60 @@
+class Link:
+    def __init__(self, val, next=None):
+        self.val = val
+        self.next = next
+
+    def __str__(self):
+        if not self.next:
+            return f"Link({self.val})"
+        return f"Link({self.val}, {self.next})"
+
+    def get_lst_val(self, lst_val):
+        lst_val.append(self.val)
+        if self.next is not None:
+            self.next.get_lst_val(lst_val)
+        return lst_val
+
+
+def merge_k_linked_lists(linked_lists):
+    """
+    Merge the given Links recursively incorporated and sorted by value
+
+    :param linked_lists: List of Links with or without next Link
+    :return: List of the sorted merged Links.
+
+
+    >>> print(merge_k_linked_lists([Link(1)]))
+    Link(1)
+
+    >>> print(merge_k_linked_lists([Link(2, Link(1))]))
+    Link(1, Link(2))
+
+    >>> print(merge_k_linked_lists([
+    ...     Link(1, Link(2, Link(5))),
+    ...     Link(3, Link(4))
+    ... ]))
+    Link(1, Link(2, Link(3, Link(4, Link(5)))))
+
+    >>> print(merge_k_linked_lists([
+    ...     Link(2, Link(4)),
+    ...     Link(2, Link(1)),
+    ...     Link(3, Link(3)),
+    ... ]))
+    Link(1, Link(2, Link(2, Link(3, Link(3, Link(4))))))
+    """
+    values = []  # 0(k*n)
+
+    for link in linked_lists:  # 0(k)
+        # lst = []
+        # for val in link.get_lst_val(lst):
+        #     values.append(val)
+        while link:  # 0(n)
+            values.append(link.val)
+            link = link.next
+    values.sort(reverse=True)  # 0(k*n*log(k*n))
+    previous_lnk = None
+    for val in values:  # 0(k*n)
+        lnk = Link(val, previous_lnk)
+        previous_lnk = lnk
+
+    return lnk  # 0(k*n*log(k*n))

practices/interview01_blank.py

@@ -0,0 +1,17 @@
+def majority_element_indexes(lst):
+    '''
+    Returns a list of the majority element indexes.
+    Majority element is the element that appears more than floor(n/2) times.
+    If there is no majority element, return an empty list.
+
+    >>> majority_element_indexes([1,1,2])
+    [0, 1]
+    >>> majority_element_indexes([1,2])
+    []
+    >>> majority_element_indexes([])
+    []
+    >>> majority_element_indexes([1,1,2,1,3,1,3])
+    [0, 1, 3, 5]
+    >>> majority_element_indexes([1,3,2,3,4,3,3,1,3])
+    [1, 3, 5, 6, 8]
+    '''

practices/interview01_solution.py

@@ -0,0 +1,22 @@
+from collections import Counter
+
+def majority_element_indexes(lst):
+    '''
+    Returns a list of the majority element indexes.
+    Majority element is the element that appears more than floor(n/2) times.
+    If there is no majority element, return an empty list.
+
+    >>> majority_element_indexes([1,1,2])
+    [0, 1]
+    >>> majority_element_indexes([1,2])
+    []
+    >>> majority_element_indexes([])
+    []
+    >>> majority_element_indexes([1,1,2,1,3,1,3])
+    [0, 1, 3, 5]
+    >>> majority_element_indexes([1,3,2,3,4,3,3,1,3])
+    [1, 3, 5, 6, 8]
+    '''
+    c = Counter(lst)
+    return [] if lst==[] or max(c, key=c.get) == min(c, key=c.get) \
+        else [idx for idx,v in enumerate(lst) if v == max(c, key=c.get)]

practices/interview02_blank.py

@@ -0,0 +1,178 @@
+def closest_lt_or_eq(obj_list, val):
+    '''
+    Must return the closest value to obj_list that is less than or equal to the number val else None
+
+    >>> print(closest_lt_or_eq([1,2,4,7,12],1))
+    1
+    >>> print(closest_lt_or_eq([1,2,4,7,12],4))
+    4
+    >>> print(closest_lt_or_eq([1,2,4,7,12],6))
+    4
+    >>> print(closest_lt_or_eq([1,2,4,7,12],12))
+    12
+    >>> print(closest_lt_or_eq([1,2,4,7,12],23))
+    None
+    >>> print(closest_lt_or_eq([1,2,4,7,12],-1))
+    None
+    '''
+
+
+def largest_one_lt(liste, val):
+    '''
+    >>> print(largest_one_lt([1,4,7,12], 1))        # nb pairs, val min
+    None
+    >>> print(largest_one_lt([1,4,7,12], 12))       # nb pairs, val max
+    7
+    >>> print(largest_one_lt([1,4,7,12], 7))        # nb pairs, val existante
+    4
+    >>> print(largest_one_lt([1,4,7,12], 6))        # nb pairs, val inexsitante
+    4
+    >>> print(largest_one_lt([1,4,7,12], 23))       # nb pairs, val supérieure
+    12
+    >>> print(largest_one_lt([1,4,7,12], 0))        # nb pairs, val inférieure
+    None
+    >>> print(largest_one_lt([1,4,5,7,12], 1))      # nb impairs, val min
+    None
+    >>> print(largest_one_lt([1,4,5,7,12], 12))     # nb impairs, val max
+    7
+    >>> print(largest_one_lt([1,4,5,7,12], 7))      # nb impairs, val existante
+    5
+    >>> print(largest_one_lt([1,4,5,7,12], 6))      # nb impairs, val inexistante
+    5
+    >>> print(largest_one_lt([1,4,5,7,12], 23))     # nb impairs, val supérieure
+    12
+    >>> print(largest_one_lt([1,4,5,7,12], 0))      # nb impairs, val inférieure
+    None
+    >>> print(largest_one_lt([4], 4))
+    None
+    >>> print(largest_one_lt([], 4))
+    None
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 1))   # nb impairs, val min
+    None
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 29))  # nb impairs, val max
+    27
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 24))  # nb impairs, val existante>12
+    22
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 21))  # nb impairs, val inexistante>12
+    20
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 5))  # nb impairs, val existante<12
+    4
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 2))  # nb impairs, val inexistante<12
+    1
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 0))  # nb impairs, val inférieure
+    None
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 30))  # nb impairs, val supérieure
+    29
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 1))   # nb pairs, val min
+    None
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 29))  # nb pairs, val max
+    27
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 24))  # nb pairs, val existante>12
+    23
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 21))  # nb pairs, val inexistante>12
+    20
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 5))  # nb pairs, val existante<12
+    4
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 2))  # nb pairs, val inexistante<12
+    1
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 0))  # nb pairs, val inférieure
+    None
+    >>> print(largest_one_lt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 30))  # nb impairs, val supérieure
+    29
+    '''
+
+
+
+def smallest_one_gt(liste, val):
+    '''
+    >>> print(smallest_one_gt([1,4,7,12], 1))        # nb pairs, val min
+    4
+    >>> print(smallest_one_gt([1,4,7,12], 12))       # nb pairs, val max
+    None
+    >>> print(smallest_one_gt([1,4,7,12], 7))        # nb pairs, val existante
+    12
+    >>> print(smallest_one_gt([1,4,7,12], 6))        # nb pairs, val inexsitante
+    7
+    >>> print(smallest_one_gt([1,4,7,12], 23))       # nb pairs, val supérieure
+    None
+    >>> print(smallest_one_gt([1,4,7,12], 0))        # nb pairs, val inférieure
+    1
+    >>> print(smallest_one_gt([1,4,5,7,12], 1))      # nb impairs, val min
+    4
+    >>> print(smallest_one_gt([1,4,5,7,12], 12))     # nb impairs, val max
+    None
+    >>> print(smallest_one_gt([1,4,5,7,12], 7))      # nb impairs, val existante
+    12
+    >>> print(smallest_one_gt([1,4,5,7,12], 6))      # nb impairs, val inexistante
+    7
+    >>> print(smallest_one_gt([1,4,5,7,12], 23))     # nb impairs, val supérieure
+    None
+    >>> print(smallest_one_gt([1,4,5,7,12], 0))      # nb impairs, val inférieure
+    1
+    >>> print(smallest_one_gt([4], 4))
+    None
+    >>> print(smallest_one_gt([], 4))
+    None
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 1))   # nb impairs, val min
+    3
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 29))  # nb impairs, val max
+    None
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 24))  # nb impairs, val existante>12
+    26
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 21))  # nb impairs, val inexistante>12
+    22
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 5))  # nb impairs, val existante<12
+    7
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 2))  # nb impairs, val inexistante<12
+    3
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 0))  # nb impairs, val inférieure
+    1
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 30))  # nb impairs, val supérieure
+    None
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 1))   # nb pairs, val min
+    3
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 29))  # nb pairs, val max
+    None
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 24))  # nb pairs, val existante>12
+    26
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 21))  # nb pairs, val inexistante>12
+    22
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 5))  # nb pairs, val existante<12
+    7
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 2))  # nb pairs, val inexistante<12
+    3
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,23,24,26,27,29], 0))  # nb pairs, val inférieure
+    1
+    >>> print(smallest_one_gt([1,3,4,5,7,8,9,12,13,14,16,17,18,20,22,24,26,27,29], 30))  # nb impairs, val supérieure
+    None
+    '''
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+