# 217. Contain Duplicate ###### tags: `Leetcode` `Easy` `Array` Link: https://leetcode.com/submissions/detail/548193708/ ## 思路 ### 思路一 先排序,然后如果有重复的就可以找到了 ### 思路二 哈希表 ## Code ### 思路一 ```java= class Solution { public boolean containsDuplicate(int[] nums) { Arrays.sort(nums); for(int i = 0;i < nums.length-1;i++){ if(nums[i] == nums[i+1]){ return true; } } return false; } } ``` ### 思路二 ```java= class Solution { public boolean containsDuplicate(int[] nums) { Set<Integer> set = new HashSet<Integer>(); for(int x : nums){ if(!set.add(x)){ return true; } } return false; } } ``` ### Result ### 思路一 Your runtime beats **27.55 %** of java submissions. Your memory usage beats **21.91 %** of java submissions. ### 思路二 Runtime: 4 ms, faster than **82.36%** of Java online submissions for Contains Duplicate. Memory Usage: 42.9 MB, less than **75.74%** of Java online submissions for Contains Duplicate.