leetcode 217. 存在重复元素 Contains Duplicate（使用c++/java/python）【使用集合】

https://leetcode-cn.com/problems/contains-duplicate/

https://leetcode.com/problems/contains-duplicate/

用set去重。

执行用时： c++ 40ms； java 23ms； python 72ms

c++

class Solution {
public:
    bool containsDuplicate(vector<int>& nums) {
        set<int> myset;
        for(int i:nums)
        {
            if(myset.find(i)!=myset.end())
                return true;
            myset.insert(i);
        }
        return false;
    }
};

java

class Solution {
    public boolean containsDuplicate(int[] nums) {
        Set<Integer> set = new HashSet<>();
        for(int i:nums)
        {
            if(set.contains(i))
                return true;
            set.add(i);
        }
        return false;
    }
}

python

class Solution:
    def containsDuplicate(self, nums):
        """
        :type nums: List[int]
        :rtype: bool
        """
        myset = set()
        for i in nums:
            if i in myset:
                return True
            myset.add(i)
        return False