package leetcode.easy;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Iterator;

import java.util.Set;

public class SingleNumber {

	@org.junit.Test

	public void test() {

		int[] nums1 = { 2, 2, 1 };

		int[] nums2 = { 4, 1, 2, 1, 2 };

		System.out.println(singleNumber1(nums1));

		System.out.println(singleNumber1(nums2));

		System.out.println(singleNumber2(nums1));

		System.out.println(singleNumber2(nums2));

		System.out.println(singleNumber3(nums1));

		System.out.println(singleNumber3(nums2));

		System.out.println(singleNumber4(nums1));

		System.out.println(singleNumber4(nums2));

	}

	public int singleNumber1(int[] nums) {

		HashSet<Integer> set = new HashSet<Integer>();

		int result = 0;

		for (int i = 0; i < nums.length; i++) {

			if (!set.contains(nums[i])) {

				set.add(nums[i]);

			} else {

				set.remove(nums[i]);

			}

		}

		Iterator<Integer> it = set.iterator();

		while (it.hasNext()) {

			result = it.next();

		}

		return result;

	}

	public int singleNumber2(int[] nums) {

		HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();

		int result = 0;

		for (int i = 0; i < nums.length; i++) {

			if (!map.containsKey(nums[i])) {

				map.put(nums[i], 1);

			} else {

				map.remove(nums[i]);

			}

		}

		Set<Integer> set = map.keySet();

		Iterator<Integer> it = set.iterator();

		while (it.hasNext()) {

			result = it.next();

		}

		return result;

	}

	public int singleNumber3(int[] nums) {

		HashSet<Integer> set = new HashSet<Integer>();

		int sumSet = 0;

		int sum = 0;

		for (int i = 0; i < nums.length; i++) {

			set.add(nums[i]);

			sum += nums[i];

		}

		Iterator<Integer> it = set.iterator();

		while (it.hasNext()) {

			sumSet += it.next();

		}

		return 2 * sumSet - sum;

	}

	public int singleNumber4(int[] nums) {

		int a = 0;

		for (int i = 0; i < nums.length; i++) {

			a ^= nums[i];

		}

		return a;

	}

}