136_Single_Number

// https://leetcode.com/problems/single-number/

class Solution {
    public int singleNumber(int[] nums) {
        int count = 0;
        HashMap<Integer,Integer> map = new HashMap<Integer,Integer>();
        for(int i=0;i<nums.length;i++)
        {
            if (map.containsKey(nums[i])==false)
                map.put(nums[i],1);
            else
            {
                map.put(nums[i],map.get(nums[i])+1);
            }
        }
        for(Map.Entry mapElement: map.entrySet()){
            int key = (int)mapElement.getKey();
            int val = (int)mapElement.getValue();
            if(val!=2)
                return key;
        }
        return 0;
    }
}


// https://leetcode.com/problems/single-number/solution/

/*
class Solution {
  public int singleNumber(int[] nums) {
    HashMap<Integer, Integer> hash_table = new HashMap<>();

    for (int i : nums) {
      hash_table.put(i, hash_table.getOrDefault(i, 0) + 1);
    }
    for (int i : nums) {
      if (hash_table.get(i) == 1) {
        return i;
      }
    }
    return 0;
  }
}

*/