adding algo

src/my_project/interviews/top_150_questions_round_22/ex_11_h_index.py

@@ -0,0 +1,16 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+
+class Solution:
+    def hIndex(self, citations: List[int]) -> int:
+
+        citations.sort(reverse=True)
+        len_cit:int = len(citations)
+        answer:int = 0
+
+        for i in range(len_cit):
+
+            if citations[i] >= i + 1:
+                answer = i + 1
+
+        return answer

src/my_project/interviews/top_150_questions_round_22/ex_12_insert_delete_get_random.py

@@ -0,0 +1,71 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+import random
+
+
+class RandomizedSet:
+
+    def __init__(self):
+        self.data_map = {} # dictionary, aka map, aka hashtable, aka hashmap
+        self.data = [] # list aka array
+
+    def insert(self, val: int) -> bool:
+
+        # the problem indicates we need to return False if the item 
+        # is already in the RandomizedSet---checking if it's in the
+        # dictionary is on average O(1) where as
+        # checking the array is on average O(n)
+        if val in self.data_map:
+            return False
+
+        # add the element to the dictionary. Setting the value as the 
+        # length of the list will accurately point to the index of the 
+        # new element. (len(some_list) is equal to the index of the last item +1)
+        self.data_map[val] = len(self.data)
+
+        # add to the list
+        self.data.append(val)
+
+        return True
+
+    def remove(self, val: int) -> bool:
+
+        # again, if the item is not in the data_map, return False. 
+        # we check the dictionary instead of the list due to lookup complexity
+        if not val in self.data_map:
+            return False
+
+        # essentially, we're going to move the last element in the list 
+        # into the location of the element we want to remove. 
+        # this is a significantly more efficient operation than the obvious 
+        # solution of removing the item and shifting the values of every item 
+        # in the dicitionary to match their new position in the list
+        last_elem_in_list = self.data[-1]
+        index_of_elem_to_remove = self.data_map[val]
+
+        self.data_map[last_elem_in_list] = index_of_elem_to_remove
+        self.data[index_of_elem_to_remove] = last_elem_in_list
+
+        # change the last element in the list to now be the value of the element 
+        # we want to remove
+        self.data[-1] = val
+
+        # remove the last element in the list
+        self.data.pop()
+
+        # remove the element to be removed from the dictionary
+        self.data_map.pop(val)
+        return True
+
+    def getRandom(self) -> int:
+        # if running outside of leetcode, you need to `import random`.
+        # random.choice will randomly select an element from the list of data.
+        return random.choice(self.data)
+
+
+
+# Your RandomizedSet object will be instantiated and called as such:
+# obj = RandomizedSet()
+# param_1 = obj.insert(val)
+# param_2 = obj.remove(val)
+# param_3 = obj.getRandom()

tests/test_150_questions_round_22/test_11_h_index_round_22.py

@@ -0,0 +1,17 @@
+import unittest
+from src.my_project.interviews.top_150_questions_round_22\
+.ex_11_h_index import Solution
+
+class hIndexTestCase(unittest.TestCase):
+
+    def test_h_index_test_1(self):
+        solution = Solution()
+        output = solution.hIndex(citations = [3,0,6,1,5])
+        target = 3
+        self.assertEqual(output, target)
+
+    def test_h_index_test_2(self):
+        solution = Solution()
+        output = solution.hIndex(citations = [1,3,1])
+        target = 1
+        self.assertEqual(output, target)