Top K frequent words solution to problem form Daily interview problem

Author: luucamay

Diff for: leetcode-daily_interview_problem/top_k_frequent_words.py

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+'''
+Top K frequent words - Daily Interview Pro
+
+Given a non-empty list of words, return the k most frequent words.
+The output should be sorted from highest to lowest frequency,
+and if two words have the same frequency, the word with lower
+alphabetical order comes first. Input will contain only lower-case letters.
+
+Example:
+Input: ["daily", "interview", "pro", "pro", "for", "daily", "pro", "problems"], k = 2
+Output: ["pro", "daily"]
+'''
+import heapq
+def top_k_frequent(words, k):
+    d = {}
+    for word in words:
+        if word in d:
+            d[word] += 1
+        else:
+            d[word] = 1
+    heap = []
+    for word in d:
+        heapq.heappush(heap, [-d[word], word])
+    answer = []
+    for i in range(k):
+        pair = heapq.heappop(heap)
+        answer.append(pair[1])
+    return answer
+
+# Test
+words = ["daily", "interview", "pro", "pro", "for", "daily", "pro", "problems"]
+k = 2
+print top_k_frequent(words, k)
+# ['pro', 'daily']
+