C# solution using HashSet

  • 0
    public class Solution {
        public int SingleNumber(int[] nums) {
            if (nums.Length == 0)
                return 0;
            if (nums.Length == 1)
                return nums[0];
            HashSet<int> hs = new HashSet<int>();
            for (int i = 0; i < nums.Length; i++)
                if (!(hs.Add(nums[i])))
            return hs.First();

  • 0

    It's a good solution but the requirement states that the optimal solution is O(n) and uses no extra memory. However, for anyone who is not familiar with XOR bitwise operations, this is a good solution. Upvoting !

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