217. Contains Duplicate

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.

思路：

排序之后比较是否前后一样（最快）

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

思路：

存到set中去重，比较前后的数组大小

public static boolean containsDuplicate(int[] nums) {         Set set = new HashSet<Integer>(); for (int i = 0; i < nums.length; i++) {         set.add(nums[i]); } return set.size() < nums.length ? true : false;}

在过程中判断contains反而会变慢。。。。