Roza-cedar

hash_practice/exercises.py

@@ -5,17 +5,56 @@ def grouped_anagrams(strings):
         Time Complexity: ?
         Space Complexity: ?
     """
-    pass
+    if len(strings) == 0:
+        return []
+    if len(strings) == 1:
+        return [[strings[0]]]
+    list1 = [strings[0]]
+    listOfLists = [list1]
+    for word in strings[1:]:
+        flag = False
+        for lists in listOfLists:
+            # check in the existing inner lists
+            if anagram_helper(word) == anagram_helper(lists[0]):
+                lists.append(word)
+                flag = True
+                break
+        # if not in the existing, create a new group
+        if not flag:
+            listOfLists.append([word])
+    return listOfLists
+
+def anagram_helper(word2):
+    freq_dict = {}
+    for letter in word2:
+        if letter not in freq_dict:
+            freq_dict[letter] = 1
+        else:
+            freq_dict[letter] += 1
+    return freq_dict
+
 
 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 log n)for sorted, O(n) to build freq dic, adding the two, the worst case will be O(n log n)
+        Space Complexity: O(n)
     """
-    pass
-
-
+    if len(nums) == 0:
+        return []
+    freq_dict = {}
+    for elem in nums:
+        if elem in freq_dict:
+            freq_dict[elem] += 1
+        else:
+            freq_dict[elem] = 1
+    # sorted returns list of tuples (key, value)
+    sorted_dict = sorted(freq_dict.items(), key=lambda item: item[1], reverse=True)
+    return_list = []
+    for index in range(k):
+         return_list.append(sorted_dict[index][0])
+    return return_list
+
 def valid_sudoku(table):
     """ This method will return the true if the table is still
         a valid sudoku table.
@@ -25,5 +64,119 @@ def valid_sudoku(table):
         Time Complexity: ?
         Space Complexity: ?
     """
-    pass
+
+    #for horizontal
+    seen_dict = {}
+    for row in table:
+        for elem in row:
+            if elem == ".":
+                continue
+            if elem in seen_dict:
+                return False
+            else:
+                seen_dict[elem] = 1
+        seen_dict = {}
+
+    # for vertical
+    seen_dict = {}
+    for col in range(len(table[0])):
+        for row in range(len(table)):
+            if table[row][col] == ".":
+                        continue
+            if table[row][col] in seen_dict:
+                    return False
+            else:
+                    seen_dict[table[row][col]] = 1
+        seen_dict = {}
+
+    # # for 3x3 grid
+    seen_dict = {}
+    for i in range(3):
+        for j in range(3):
+            if table[i][j] == ".":
+                continue
+            if table[i][j] in seen_dict:
+                return False
+            else:
+                seen_dict[table[i][j]] = 1
+
+    seen_dict = {}
+    for i in range(3):
+        for j in range(3, 6):
+            if table[i][j] == ".":
+                continue
+            if table[i][j] in seen_dict:
+                return False
+            else:
+                seen_dict[table[i][j]] = 1
+
+    seen_dict = {}
+    for i in range(3):
+        for j in range(6,9):
+            if table[i][j] == ".":
+                continue
+            if table[i][j] in seen_dict:
+                return False
+            else:
+                seen_dict[table[i][j]] = 1
+
+    seen_dict = {}
+    for i in range(3,6):
+        for j in range(3):
+            if table[i][j] == ".":
+                continue
+            if table[i][j] in seen_dict:
+                return False
+            else:
+                seen_dict[table[i][j]] = 1
 
+    seen_dict = {}
+    for i in range(3,6):
+        for j in range(3, 6):
+            if table[i][j] == ".":
+                continue
+            if table[i][j] in seen_dict:
+                return False
+            else:
+                seen_dict[table[i][j]] = 1
+
+    seen_dict = {}
+    for i in range(3,6):
+        for j in range(6, 9):
+            if table[i][j] == ".":
+                continue
+            if table[i][j] in seen_dict:
+                return False
+            else:
+                seen_dict[table[i][j]] = 1
+
+    seen_dict = {}
+    for i in range(6,9):
+        for j in range(3):
+            if table[i][j] == ".":
+                continue
+            if table[i][j] in seen_dict:
+                return False
+            else:
+                seen_dict[table[i][j]] = 1
+
+    seen_dict = {}
+    for i in range(6,9):
+        for j in range(3, 6):
+            if table[i][j] == ".":
+                continue
+            if table[i][j] in seen_dict:
+                return False
+            else:
+                seen_dict[table[i][j]] = 1
+
+    seen_dict = {}
+    for i in range(6,9):
+        for j in range(6, 9):
+            if table[i][j] == ".":
+                continue
+            if table[i][j] in seen_dict:
+                return False
+            else:
+                seen_dict[table[i][j]] = 1
+    return True