rock - mana

hash_practice/exercises.py

@@ -2,18 +2,55 @@
 def grouped_anagrams(strings):
     """ This method will return an array of arrays.
         Each subarray will have strings which are anagrams of each other
-        Time Complexity: ?
-        Space Complexity: ?
+        Time Complexity: O(n)
+        Space Complexity: O(n)
     """
-    pass
+    anagram_table = {}
+    anagram_values = []
+
+    for word in strings:
+        key = ''.join(sorted(word))
+        if key in anagram_table.keys():
+            anagram_table[key].append(word)
+        else:
+            anagram_table[key] = []
+            anagram_table[key].append(word)
+
+    for value in anagram_table.values():
+        anagram_values.append(value)
+
+    return anagram_values
 
 def top_k_frequent_elements(nums, k):
     """ This method will return the k most common elements
         In the case of a tie it will select the first occuring element.
-        Time Complexity: ?
-        Space Complexity: ?
+        Time Complexity: O(n)
+        Space Complexity: O(n)
     """
-    pass
+    numbers_dict = {}
+    frequency_dict = {}  
+    return_list = []
+
+    for num in nums:
+        if num in numbers_dict:
+            numbers_dict[num] += 1
+        else:
+            numbers_dict[num] = 1
+
+    for key, value in numbers_dict.items():
+        if value not in frequency_dict:
+            frequency_dict[value] = [key]
+        else:
+            frequency_dict[value].append(key)
+
+    for i in range(len(nums), 0, -1): 
+        if i in frequency_dict:
+            return_list.extend(frequency_dict[i])
+
+        if len(return_list) >= k:
+            break
+
+    return return_list
 
 
 def valid_sudoku(table):
@@ -22,8 +59,26 @@ def valid_sudoku(table):
         Each element can either be a ".", or a digit 1-9
         The same digit cannot appear twice or more in the same 
         row, column or 3x3 subgrid
-        Time Complexity: ?
-        Space Complexity: ?
+        Time Complexity: O(n)
+        Space Complexity: O(n)
     """
-    pass
+    for i in range(len(table)):
+        row = {}
+        column = {}
+        block = {}
+        row_cube = 3 * (i//3)
+        column_cube = 3 * (i%3)
+        for j in range(len(table)):
+            if table[i][j]!='.' and table[i][j] in row:
+                return False
+        row[table[i][j]] = 1
+        if table[j][i]!='.' and table[j][i] in column:
+            return False
+        column[table[j][i]] = 1
+        rc= row_cube+j//3
+        cc = column_cube + j%3
+        if table[rc][cc] in block and table[rc][cc]!='.':
+            return False
+        block[table[rc][cc]]=1
+    return True
 

tests/test_top_k_frequent_elements.py

@@ -51,12 +51,13 @@ def test_will_work_for_list_with_k_elements_all_unique():
 def test_returns_2_3_for_1_2_2_2_3_3_3():
     # Arrange
     numbers = [1, 2, 2, 2, 3, 3, 3]
-    k = 2
+    k = 1
 
     # Act
     answer = top_k_frequent_elements(numbers, k)
 
     # Assert
     answer.sort()
+    print(answer)
     assert answer == [2, 3]