Added Majority Voting Algorithm

other/majority_vote_algorithm.py

@@ -0,0 +1,37 @@
+"""
+This is Booyer-Moore Majority Vote Algorithm. The problem statement goes like this:
+Given an integer array of size n, find all elements that appear more than ⌊ n/k ⌋ times.
+We have to solve in O(n) time and O(1) Space.
+URL : https://en.wikipedia.org/wiki/Boyer%E2%80%93Moore_majority_vote_algorithm
+"""
+from collections import Counter
+
+
+def majority_vote(votes: list[int], votes_needed_to_win: int) -> list[int]:
+    """
+    >>> majority_vote([1, 2, 2, 3, 1, 3, 2], 3)
+    [2]
+    >>> majority_vote([1, 2, 2, 3, 1, 3, 2], 2)
+    []
+    >>> majority_vote([1, 2, 2, 3, 1, 3, 2], 4)
+    [1, 2, 3]
+    """
+    majority_candidate_counter: Counter[int] = Counter()
+    for vote in votes:
+        majority_candidate_counter[vote] += 1
+        if len(majority_candidate_counter) == votes_needed_to_win:
+            majority_candidate_counter -= Counter(set(majority_candidate_counter))
+    majority_candidate_counter = Counter(
+        vote for vote in votes if vote in majority_candidate_counter
+    )
+    return [
+        vote
+        for vote in majority_candidate_counter
+        if majority_candidate_counter[vote] > len(votes) / votes_needed_to_win
+    ]
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()