Leetcode Everyday: 217. Contains Duplicate

原创于 2016-05-12 12:26:45 发布 · 209 阅读

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本文介绍了一种使用排序方法来判断数组中是否存在重复元素的算法，并探讨了如何通过哈希集合实现O(n)的时间复杂度。

https://leetcode.com/problems/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.

public class Solution {
    public boolean containsDuplicate(int[] nums) {
        if(nums.length<2) return false;
        Arrays.sort(nums);
        for(int i = 1; i<nums.length;i++){
            if (nums[i]==nums[i-1]) return true;
        }
        return false;
    }
}

We can use a hashset to achieve O(n) time complexity.