hashset

Question:

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.

//RJ

public class Solution {
    public boolean containsDuplicate(int[] nums) {
      int count=0;
        boolean check=false;
        TreeSet<String> h=new TreeSet<String>();
         
        for(int i=0;i<nums.length;i++) {
            h.add(""+nums[i]);
        }
        if(h.size()<nums.length) {
            check=true;
        }
        if(nums.length==1)
            check=false;
         
        return check;
    }
}

//AC

public boolean containsDuplicate_(int[] nums)
{
    Set<Integer> appearedNum = new HashSet<Integer>();
    for(int i = 0; i < nums.length; i++){
        if(!appearedNum.contains(nums[i])){
            appearedNum.add(nums[i]);
        } else return true;
    }
    return false;
}

hashset

原文：http://www.cnblogs.com/qinyongzhu/p/4948373.html