@@ -0,0 +1,901 @@
+/**%0A * Given an array of integers, find if the array contains any duplicates. Your function should return true if %0A * any value appears at least twice in the array, and it should return false if every element is distinct.%0A */%0Apublic class Solution %7B%0A  public boolean containsDuplicate(int%5B%5D nums) %7B%0A      if(nums == null %7C%7C nums.length == 0) return false;%0A      Set%3CInteger%3E pool = new HashSet%3CInteger%3E();%0A      for(int i : nums) %7B%0A          if(!pool.contains(i))%0A              pool.add(i);%0A          else%0A              return true;%0A      %7D%0A      return false;%0A  %7D%0A%7D%0A%0A// a better solution%0Apublic class Solution %7B%0A    public boolean containsDuplicate(int%5B%5D nums) %7B%0A        if(nums == null %7C%7C nums.length == 0) return false;%0A        Set%3CInteger%3E pool = new HashSet%3CInteger%3E();%0A        for(int i : nums) %7B%0A            if(!pool.add(i))%0A                return true;%0A        %7D%0A        return false;%0A    %7D%0A%7D%0A

Create 217.java