@@ -0,0 +1,427 @@
+package leetcode;%0A%0Aimport java.util.HashSet;%0Aimport java.util.Set;%0A%0A/**%0A * https://leetcode.com/problems/contains-duplicate/%0A */%0Apublic class Problem217 %7B%0A    public boolean containsDuplicate(int%5B%5D nums) %7B%0A        Set%3CInteger%3E set = new HashSet%3C%3E();%0A        for (int num : nums) %7B%0A            if (set.contains(num)) %7B%0A                return true;%0A            %7D%0A            set.add(num);%0A        %7D%0A        return false;%0A    %7D%0A%7D%0A

Solve problem 217