Single number i

bit_manipulation/single_number.py

@@ -0,0 +1,41 @@
+"""
+ Given a non-empty array of integers nums, every element
+ appears twice except for one. Find that single one
+
+ You must implement a solution with a linear runtime complexity
+ and use only constant extra space.
+
+ Reference: https://leetcode.com/problems/single-number/
+"""
+
+
+def single_number(nums: list) -> int:
+ """
+ :param nums: A non-empty array of any integers nums,
+ every element appears twice except for one.
+ :return: element that appears only one time
+
+ Examples:
+ Example 1
+ >>> print(single_number([1, 3, 3, 2, 6, 2, 1]))
+ 6
+
+ Example 2
+ >>> print(single_number([12, 1, 1, 7, 1, 12, 1]))
+ 7
+
+ Example 3
+ >>> print(single_number([6]))
+ 6
+ """
+
+ result = 0
+ for el in nums:
+ result ^= el
+ return result
+
+
+if __name__ == "__main__":
+ import doctest
+
+ doctest.testmod()