Given an array of integers, find if the array contains any duplicates.

Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct.

Example 1:
Input: [1,2,3,1]
Output: true

Example 2:
Input: [1,2,3,4]
Output: false

Example 3:
Input: [1,1,1,3,3,4,3,2,4,2]
Output: true

/*
 * 217. Contains Duplicate
 * https://leetcode.com/problems/contains-duplicate/
 * https://realneo.me/217-contains-duplicate/
 */

import java.util.HashSet;
import java.util.Set;

public class ContainsDuplicate {
    public static void main(String[] args) {
        ContainsDuplicate solution = new ContainsDuplicate();

        int[] nums;
        nums = new int[]{1, 2, 3, 1};
        System.out.println(solution.containsDuplicate(nums));
        nums = new int[]{1, 2, 3, 4};
        System.out.println(solution.containsDuplicate(nums));
        nums = new int[]{1, 1, 1, 3, 3, 4, 3, 2, 4, 2};
        System.out.println(solution.containsDuplicate(nums));
    }

    private boolean containsDuplicate(int[] nums) {
        Set<Integer> map = new HashSet<>();

        for (int i : nums)
            if (map.contains(i))
                return true;
            else
                map.add(i);

        return false;
    }
}