ContainsDuplicate217.java

/**
 * 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.
 */

public class ContainsDuplicate217 {
    public boolean containsDuplicate(int[] nums) {
        Set<Integer> set = new HashSet<>();
        for (int n: nums) {
            if (set.contains(n)) {
                return true;
            } else {
                set.add(n);
            }
        }
        return false;
    }


    public boolean containsDuplicate2(int[] nums) {
        Arrays.sort(nums);
        for (int i = 0; i < nums.length - 1; ++i) {
            if (nums[i] == nums[i + 1]) return true;
        }
        return false;
    }

}