Moore

Moore's algorithm.py

@@ -0,0 +1,34 @@
+def majority_element(nums):
+    """
+    Returns the majority element in a given list using Moore's Voting Algorithm.
+
+    Args:
+    nums (list): List of integers.
+
+    Returns:
+    int: Majority element, if it exists. None otherwise.
+    """
+    # initialize variables
+    candidate = None
+    count = 0
+
+    # iterate through list
+    for num in nums:
+        if count == 0:
+            # set new candidate
+            candidate = num
+        count += 1 if num == candidate else -1
+
+    # verify candidate is actually the majority element
+    if nums.count(candidate) > len(nums) // 2:
+        return candidate
+    else:
+        return None
+nums = [2,2,1,1,1,2,2]
+print(majority_element(nums)) # output: 2
+
+nums = [3,3,4,2,4,4,2,4,4]
+print(majority_element(nums)) # output: 4
+
+nums = [1,2,3,4,5]
+print(majority_element(nums)) # output: None